Finalist: Opinion Staff of The New York Times, notably W. J. Hennigan and Kathleen Kingsbury

By W.J. Hennigan

If it seems alarmist to anticipate the horrifying aftermath of a nuclear attack, consider this: The United States and Ukraine governments have been planning for this scenario for at least two years.

In the fall of 2022, a U.S. intelligence assessment put the odds at 50-50 that Russia would launch a nuclear strike to halt Ukrainian forces if they breached its defense of Crimea. Preparing for the worst, American officials rushed supplies to Europe. Ukraine has set up hundreds of radiation detectors around cities and power plants, along with more than 1,000 smaller hand-held monitors sent by the United States.

Nearly 200 hospitals in Ukraine have been identified as go-to facilities in the event of a nuclear attack. Thousands of doctors, nurses and other workers have been trained on how to respond and treat radiation exposure. And millions of potassium iodide tablets, which protect the thyroid from picking up radioactive material linked with cancer, are stockpiled around the country.

But well before that — just four days after Russia launched its invasion of Ukraine, in fact — the Biden administration had directed a small group of experts and strategists, a “Tiger Team,” to devise a new nuclear “playbook” of contingency plans and responses. Pulling in experts from the intelligence, military and policy fields, they pored over years-old emergency preparedness plans, weapon-effects modeling and escalation scenarios, dusting off materials that in the age of counterterrorism and cyberwarfare were long believed to have faded into irrelevance.

The playbook, which was coordinated by the National Security Council, now sits in the Eisenhower Executive Office Building, next to the West Wing of the White House. It has a newly updated, detailed menu of diplomatic and military options for President Biden — and any future president — to act upon if a nuclear attack occurs in Ukraine.

At the heart of all of this work is a chilling conclusion: The possibility of a nuclear strike, once inconceivable in modern conflict, is more likely now than at any other time since the Cold War. “We've had 30 pretty successful years keeping the genie in the bottle,” a senior administration official on the Tiger Team said. While both America and Russia have hugely reduced their nuclear arsenals since the height of the Cold War, the official said, “Right now is when nuclear risk is most at the forefront.”

Russian President Vladimir Putin reminded the world of this existential danger last week when he publicly warned of nuclear war if NATO deepened its involvement in Ukraine.

The risk of nuclear escalation in Ukraine, while now low, has been a primary concern for the Biden administration throughout the conflict, details of which are being reported here for the first time. In a series of interviews over the past year, U.S. and Ukrainian officials spoke on condition of anonymity to discuss internal planning, diplomacy and ongoing security preparations.

And while it may cause sleepless nights in Washington and Kyiv, most of the world has barely registered the threat. Perhaps it’s because an entire generation came of age in a post-Cold War world, when the possibility of nuclear war was thought to be firmly behind us. It is time to remind ourselves of the consequences in order to avoid them.

Imagine a nuclear weapon is launched.

A nuclear warhead, which has more than half of the Hiroshima bomb’s explosive power, fits snugly into the cone of a short-range missile.

The missile is launched. Once its solid-fuel rocket motor burns out, the warhead plunges back toward Earth.

A third of a mile above the ground, it explodes.

Its plutonium core and surrounding contents — so delicately pieced together inside — convert into ionized gas and electromagnetic waves within a millisecond.

A brilliant white flash envelops the sky for miles, briefly blinding everyone who witnesses it.

A roar equal to 10,000 tons of TNT quakes the ground below. A massive fireball blooms so quickly that it seems instantaneous.

Temperatures inside the explosion reach millions of degrees, hotter than the surface of the sun.

Nearly everything flammable below ignites: wood, plastics, oil. Small animals burst into flame, then turn to ash.

Ruptured gas and downed electricity lines fuel an inferno that can rage for miles.

The firestorm consumes so much oxygen that it can suffocate people sheltering inside their cars or homes.

Then there is the shock wave, a rumbling force that expands in every direction, racing at supersonic speeds.

Buildings, trees and other living things are torn apart and thrown at one another.

Near the explosion’s epicenter, buildings heave, sag and crumble. Scalding hot glass and debris shoot like shrapnel into everything in their path.

Dry leaves crackle like popcorn and disappear in the blazing heat.

The wreckage — what once was asphalt, steel, soil, glass, flesh and bone — is suctioned into the roiling stem of a mushroom cloud rising for miles.

The cloud appears like a living thing. Its colors change from white to yellow to red to black, billowing into the sky until it eclipses the sun.

Screams for help — and for death — can be heard everywhere, but help is not on the way. Finding a doctor or a nurse is nearly impossible. Most medical workers in the immediate area are dead or injured. Those who survive are quickly overwhelmed.

Then, darkness. There’s a discordant ringing. The air is thick with smoke and debris. Breathing in is difficult — spit out a mouthful of dust and glass fragments, only to take in another.

Even after last week’s nuclear threat, few believe that Mr. Putin will wake up one day and decide to lob megaton warheads at Washington or European capitals in retaliation for supporting Ukraine. What Western allies see as more likely is that Russia will use a so-called tactical nuclear weapon, which is less destructive and designed to strike targets over short distances to devastate military units on the battlefield.

The strategic thinking behind those weapons is that they are far less damaging than city-destroying hydrogen bombs and therefore more “usable” in warfare. The United States estimates Russia has a stockpile of up to 2,000 tactical nuclear warheads, some small enough they fit in an artillery shell.

But the detonation of any tactical nuclear weapon would be an unprecedented test of the dogma of deterrence, a theory that has underwritten America’s military policy for the past 70 years. The idea stipulates that adversaries are deterred from launching a nuclear attack against the United States — or more than 30 of its treaty-covered allies — because by doing so they risk an overwhelming counterattack.

Possessing nuclear weapons isn’t about winning a nuclear war, the theory goes; it’s about preventing one. It hinges upon a carefully calibrated balance of terror among nuclear states.

After the nuclear age began in 1945, the United States and the Soviet Union were locked in an arms race. Each side amassed tens of thousands of nuclear arms.

Over time, nuclear weapons became symbols of national power and prestige. Other nations in Europe and Asia developed their own arsenals.

The dangerous, costly arms buildup pushed Washington and Moscow to the brink of confrontation, before a gradual warming in relations led to mutual reductions.

In the decades since, overall nuclear stockpiles have shrunk, but the number of nuclear powers has increased to nine.

If Mr. Putin dropped a nuclear weapon on Ukraine — a nonnuclear nation that’s not covered by anyone’s nuclear umbrella — what then? If deterrence fails, how is it possible to reduce the risk of one attack escalating into a global catastrophe?

We might find an answer in the autumn of 2022, when fears of Russia’s nuclear use in Ukraine were most palpable. A lightning Ukrainian military counteroffensive had reclaimed territory from the Russians in the northeastern region of Kharkiv. The Ukrainians were on the cusp of breaching Russian defense lines at Kherson in the south, possibly causing a second Russian retreat that could signal an imminent broader military collapse.

U.S. intelligence estimated that if Ukraine’s fighters managed to break through Russian defenses — and were on the march to the occupied Crimean Peninsula, where the Russian Black Sea Fleet is based — it came down to a coin flip whether or not Russia would launch a tactical nuclear weapon to stop them, senior administration officials said.

Moscow has made implicit and explicit nuclear threats throughout the war to scare off Western intervention. Around this time, however, a series of frightening episodes took place.

On Oct. 23, Defense Minister Sergei Shoigu of Russia made a flurry of phone calls to the defense chiefs of four NATO nations, including Defense Secretary Lloyd Austin, to say Russia had indications that Ukrainian fighters could detonate a dirty bomb — a conventional explosive wrapped in radioactive material — on their own territory to frame Moscow.

American intelligence also intercepted chatter around then among Russian military leaders about using a tactical nuclear weapon, according to current and former Biden administration officials. General Austin and the Joint Chiefs of Staff chairman, Gen. Mark Milley, held three phone calls in four days with Russian counterparts during this tense period.

Believing the Russians were building an unfounded pretext for their own nuclear attack, the Biden administration quickly began a multilateral effort with allies, adversaries and nations in between to de-escalate the situation and try to talk Moscow out of it. For nearly a week, Biden aides pulled all-nighters at the White House, coordinating high-level conversations and planning for the worst: the detonation of a small nuclear device in Ukrainian territory that had the power of a few kilotons or less.

Many in the administration believed the Kremlin’s dirty bomb ploy posed the greatest risk of nuclear war since the 1962 Cuban missile crisis. State Department officials traveled to Poland to ensure that medical supplies and radiation equipment were rushed over the border. The Energy Department sent equipment to collect potential debris so that it could be later analyzed by American scientists for weapon design characteristics and the origin of the nuclear material. U.S. Strategic Command, which oversees nuclear operations, directed a team of experts (cheekily named The Writers’ Club, because their findings were written up daily for the Pentagon leadership) to assess the risk and determine which conditions would trigger Russia to go nuclear.

While cautions about the potential withering economic, diplomatic and military consequences were delivered in private to Moscow, administration officials also publicly sounded alarm bells.

The administration’s diplomatic push was coupled with efforts by leaders of several nations, including China, India and Turkey, to explain to Mr. Putin’s government the potential costs if he were to go through with a nuclear attack. That November, the director of the Central Intelligence Agency, William J. Burns, met with his Russian counterpart in Turkey, where he conveyed a similar warning. On Nov. 16, the Group of 20 released a joint statement:

If the Russian leader was indeed inching toward the brink, he stepped back.

Imagine the damage the weapon would wreak on people and the environment.

The toll of a 10-kiloton blast on a military target near a city could be thousands dead, even more wounded. Roads, tunnels and railways are impassable because of debris and destruction. It might be days before rescue workers can venture safely into affected areas.

Cell towers and utility poles are knocked over and disconnected, causing widespread power failures. The electromagnetic pulse released from the detonation cripples electronic equipment within roughly a one-mile radius from the epicenter.

The thousands of unburied dead, the open sewage and the fetid water are a breeding ground for disease and growth in insect populations that have a higher tolerance than humans for radiation. Flies appear en masse, laying eggs in corpses and the open burn wounds of survivors.

The debris churned up by a nuclear blast, along with soot and ash from the raging fires, falls back to earth as thick, black water droplets laced with radioactive material. Black-rain showers can fall miles away from ground zero, staining nearly everything they touch.

Radiation sickness begins with bouts of nausea, vomiting and diarrhea. Days or weeks after exposure, people who look fine can suddenly lose hunks of hair, become anemic and weak, and begin bleeding internally. Their immune systems can fail, rendering them helpless against the infectious diseases that start to spread: dysentery, typhoid, cholera.

Some pregnant women who are near the blast later give birth to babies with microcephaly and other defects. Cancer of all kinds can appear decades later.

If radioactive contamination from the initial blast passes through the food chain via animals and plant roots, damage to the ecosystem can linger for years.

What took place to prevent a nuclear attack that fall was a rare moment of consensus on an issue on which world leaders seem to be moving farther apart. Russia is replacing its Soviet-era hardware with new jets, missiles and submarines. And the other eight nations that have nuclear weapons are believed to be enhancing their arsenals in parts of the world that are already on edge.

India, which has continuing tensions over its borders with China and Pakistan, is fielding longer-range weapons.

Pakistan is developing new ballistic missiles and expanding nuclear production facilities.

North Korea, which has an arsenal of several hundred missiles and dozens of nuclear warheads, regularly threatens to attack South Korea, where the U.S. keeps about 28,500 troops.

China, which has publicly expressed its desire to control the U.S.-allied island of Taiwan by force if necessary, is increasing its nuclear arsenal at a “scale and pace unseen since the U.S.-Soviet nuclear arms race that ended in the late 1980s,” the Congressional Commission on the Strategic Posture of the United States concluded in October.

So while Washington has been helping Ukraine prepare for a nuclear attack, Taiwan or South Korea could be next. The National Security Council has already coordinated contingency playbooks for possible conflicts that could turn nuclear in Taiwan, the Korean Peninsula and the Middle East. Iran, which has continued its nuclear program amid Israel’s war on Hamas in Gaza, has amassed enough enriched uranium to build several weapons if and when it chooses.

During this time of widening conflict, the rising nuclear threat is especially destabilizing: A nuclear explosion in Ukraine or Gaza, where tens of thousands of civilians have already been killed or injured, would sizeably escalate either conflict and its humanitarian toll.

The world has been through a version of this moment before. The last nuclear standoff during the Cold War was cooled in part because of numerous nonproliferation efforts and arms control agreements between the United States and the former Soviet Union. The two nations, recognizing the terrifying situation they were in, worked to identify weapons that were mutually menacing and simply agreed to eliminate them. Nuclear warhead numbers plummeted to 12,500 today from roughly 70,400 in 1986.

Now that shared safety net of treaties and agreements is nearly gone. After a decade of diplomatic breakdown and military antagonism, only one major arms treaty between the United States and Russia remains — New START, which Mr. Putin suspended Russia’s participation in last year. The treaty is set to expire in February 2026.

That means we are just two years away from a world in which there are no major treaty limits on the number of strategic nuclear weapons the United States and Russia deploy. Already today, because of the New START suspension, the two nations disclose little information about their arsenals to each other and do not engage in talks for further agreements. If nuclear deterrence — however flawed a concept it may be — is to work, transparency about nations’ capabilities is critical. Without better communication, the risk of rapid escalation and miscalculation will grow.

The danger of nuclear use in Ukraine fluctuates. It waned after Ukraine’s drive to recapture territory and sever Russia’s supply lines to Crimea was stopped short. But if the momentum swings back in Ukraine’s favor, or if Mr. Putin feels threatened by increased Western intervention, it could rise again. A U.S. intelligence report declassified late last year estimated Russia had lost around 315,000 troops to death or injury in Ukraine since 2022. That’s nearly 90 percent of its prewar force, along with at least 20 warships, thousands of battle tanks and heavy weapons — all major losses that could create more dependency on its tactical nuclear arsenal.

Imagine the ripple effect of one nuclear warhead on the world — on where people live, what
they eat, their sense of safety.

Few nations on earth are unaffected. If the strike happens in a country like Ukraine, among the largest grain-exporting nations in the world, the impact spreads quickly. The attack prompts an agricultural embargo to contain potentially contaminated crops, creating a domino effect of food shortages that spread across the Middle East, South Asia, North Africa and West Africa.

Fear is as dangerous as contamination itself: Panic over radiation exposure and its long-term effects drives people from their homes, regardless of whether the threat in their community is real or not. Border crossings are quickly overrun.

Anxieties over a wider nuclear war immediately spike, causing the New York Stock Exchange to plunge. Lockdown orders trigger a rush on groceries, wiping markets’ shelves clean.

No one can say what would happen next. If it was Vladimir Putin who launched an attack on Ukraine, the U.S. has warned there would be “catastrophic consequences.” But the response might not be nuclear. It could be a devastating aerial bombardment aimed at Russia’s naval fleet, or Washington could decide to target a base in Belarus, where Russia has recently deployed nuclear weapons, avoiding a direct attack on Russian territory.

A tit-for-tat escalation, once touched off, is difficult to stop. If the end result was a thermonuclear exchange between nuclear powers, like the U.S. and Russia, the impact on humanity would be swift and long-lasting.

Even a limited nuclear war could be catastrophic. A 2022 scientific study found that if 100 Hiroshima-size bombs — less than 1 percent of the estimated global nuclear arsenal — were detonated in certain cities, they could generate more than five million tons of airborne soot, darkening the skies, lowering global temperatures and creating the largest worldwide famine in history.

An estimated 27 million people could immediately die, and as many as 255 million people may starve within two years.

This isn't an easy time for adversaries to be making big leaps of faith, but history shows it’s not impossible to forge deals amid international crises.

The Limited Test Ban Treaty, which prohibits nuclear tests in the atmosphere, in space and underwater, was signed by the United States, Britain and the former Soviet Union in 1963, less than a year after the Cuban missile crisis. Negotiations over the first Strategic Arms Limitation Talks, which froze the number of American and Soviet long-range, nuclear-capable missiles, were concluded less than two months after the United States bombed Haiphong Harbor in Vietnam in 1972, damaging some Soviet ships. Several close calls in Europe during the Cold War contributed to a sweeping collection of agreements between Washington and Moscow that capped the number of each nation’s strategic weapons, opened communication channels and amplified monitoring and verification measures.

China’s aggressive nuclear buildup has complicated the strategic balance of the Cold War, raising questions in the United States about how to handle a three-way competition. In June, Jake Sullivan, President Biden’s national security adviser, publicly offered to hold nuclear arms control negotiations with Russia and China — one-on-one or multilaterally — without preconditions. The proposal has resulted in only preliminary discussions with the Chinese and was met with outright dismissal from the Russians, according to administration officials.

Nuclear arms treaties typically take months or years to negotiate. And while the agreements don’t solve everything, they do allow governments to gain insights and assurances about an adversary’s stockpile that they otherwise wouldn’t have. Left in the dark, governments are forced to plan for the worst, building offensive and defensive capabilities.

THIS ISN’T AN easy time for adversaries to be making big leaps of faith, but history shows it’s not impossible to forge deals amid international crises.

The Limited Test Ban Treaty, which prohibits nuclear tests in the atmosphere, in space and underwater, was signed by the United States, Britain and the former Soviet Union in 1963, less than a year after the Cuban missile crisis. Negotiations over the first Strategic Arms Limitation Talks, which froze the number of American and Soviet long-range, nuclear-capable missiles, were concluded less than two months after the United States bombed Haiphong Harbor in Vietnam in 1972, damaging some Soviet ships. Several close calls in Europe during the Cold War contributed to a sweeping collection of agreements between Washington and Moscow that capped the number of each nation’s strategic weapons, opened communication channels and amplified monitoring and verification measures.

China’s aggressive nuclear buildup has complicated the strategic balance of the Cold War, raising questions in the United States about how to handle a three-way competition. In June, Jake Sullivan, President Biden’s national security adviser, publicly offered to hold nuclear arms control negotiations with Russia and China — one-on-one or multilaterally — without preconditions. The proposal has resulted in only preliminary discussions with the Chinese and was met with outright dismissal from the Russians, according to administration officials.

Nuclear arms treaties typically take months or years to negotiate. And while the agreements don’t solve everything, they do allow governments to gain insights and assurances about an adversary’s stockpile that they otherwise wouldn’t have. Left in the dark, governments are forced to plan for the worst, building offensive and defensive capabilities.

The United States is now preparing to build new nuclear warheads for the first time since 1991, part of a decades-long program to overhaul its nuclear forces that’s estimated to cost up to $2 trillion. The outline of that plan was drawn up in 2010 — in a much different security environment than what the country faces today. This administration, or the next one, could make the political case that even more weapons need to be built in response to the expansion and modernization of other nations’ arsenals, particularly Russia’s and China’s.

Behind a nondescript door on the fifth floor of the State Department building in Washington, down the hall from the former offices of the director of the Manhattan Project, a windowless control room provides a direct channel between the world’s two biggest nuclear powers.

The National and Nuclear Risk Reduction Center was established in 1988 as a 24-hour watch station to facilitate the information exchange required by various arms control treaties and security-building agreements, mostly between the United States and Russia.

With a Russian translator always on the floor, the center once buzzed with more than 1,000 messages a year regarding the testing, movement and maintenance of Russia’s weapons, missiles and bombers. Last year, after the abandonment of New START, the center received fewer than a dozen of those messages.

Today, the mechanisms of peace aren't moving as swiftly as the machinery of war.

The National and Nuclear Risk Reduction Center is adding translating services for Persian, Mandarin, Korean and other languages in case more nuclear nations express an interest in sharing information to reduce the risk of an inadvertent conflict.

But for now, those ambitions are unrealized, and the communication lines remain quiet.

W.J. Hennigan writes about national security issues for Opinion from Washington, D.C. He has reported from more than two dozen countries, covering war, the arms trade and the lives of U.S. service members. Additional reporting by Spencer Cohen. A selection of sources consulted in reporting this project can be found here.

National and Nuclear Risk Reduction Center photographed by An-My Lê for The New York Times. Illustrations by Tim McDonagh. Animation by Jil Tai. Phone call: Robert L. Knudsen/U.S. National Archives and Records Administration (test ban). Treaty photos: Corbis/Getty Images (SALT); Bettmann/Getty Images (INF); Joe Klamar/Agence France-Presse — Getty Images (NEW START). Videos: The Union Herald, via YouTube; RTVI News, via YouTube; CGTN, via YouTube; Global News, via YouTube; Pakistan Armed Forces, via YouTube; AFP, via YouTube.

Edited by Krista Mahr, Kathleen Kingsbury and Meeta Agrawal. Produced by Jessia Ma, Kate Elazegui, Shoshana Schultz, Quoctrung Bui, Jacqueline Bates and Ana Becker.

This Times Opinion series is funded through philanthropic grants from the Carnegie Corporation of New York, Outrider Foundation and the Prospect Hill Foundation. Funders have no control over the selection or focus of articles or the editing process and do not review articles before publication. The Times retains full editorial control.

By Kathleen Kingsbury

The threat of nuclear war has dangled over humankind for much too long. We have survived so far through luck and brinkmanship. But the old, limited safeguards that kept the Cold War cold are long gone. Nuclear powers are getting more numerous and less cautious. We’ve condemned another generation to live on a planet that is one grave act of hubris or human error away from destruction without demanding any action from our leaders. That must change.

In New York Times Opinion’s latest series, At the Brink, we’re looking at the reality of nuclear weapons today. It’s the culmination of nearly a year of reporting and research. We plan to explore where the present dangers lie in the next arms race and what can be done to make the world safer again.

W.J. Hennigan, the project's lead writer, begins that discussion today by laying out what’s at stake if a single nuclear weapon were used, as well as revealing for the first time details about how close U.S. officials thought the world came to breaking the decades-long nuclear taboo.

Russia’s president, Vladimir Putin, threatened in his 2024 annual speech that more direct Western intervention in Ukraine could lead to nuclear conflict. Yet an American intelligence assessment suggests the world may have wandered far closer to the brink of a nuclear launch more than a year earlier, during the first year of Mr. Putin's invasion.

This is the first telling of the Biden administration’s efforts to avoid that fate, and had they failed, how they hoped to contain the catastrophic aftermath. Mr. Hennigan explores what happened during that tense time, what officials were thinking, what they did and how they’re approaching a volatile future.

Within two years, the last major remaining arms treaty between the United States and Russia is to expire. Yet amid mounting global instability and shifting geopolitics, world leaders aren’t turning to diplomacy. Instead, they have responded by building more technologically advanced weapons. The recent intelligence on Russia’s development of a space-based nuclear weapon is the latest reminder of the enormous power these weapons continue to wield over our lives.

There is no precedent for the complexity of today’s nuclear era. The bipolarity of the Cold War has given way to a great-power competition with far more emerging players. With the possibility of Donald Trump returning as president, Iran advancing its nuclear development and China on track to stock its arsenal with 1,000 warheads by 2030, German and South Korean officials have wondered aloud if they should have their own nuclear weapons, as have important voices in Poland, Japan and Saudi Arabia.

The latest generation of nuclear technology can still inflict unspeakable devastation. Artificial intelligence could someday automate war without human intervention. No one can confidently predict how and if deterrence will work under these dynamics or even what strategic stability will look like. A new commitment to what could be years of diplomatic talks will be needed to establish new terms of engagement.

Over the past several months, I’ve been asked, including by colleagues, why I want to raise awareness on nuclear arms control when the world faces so many other challenges — climate change, rising authoritarianism and economic inequality, as well as the ongoing wars in Ukraine and the Middle East.

Part of the answer is that both of those active conflicts would be far more catastrophic if nuclear weapons were introduced into them. Consider Mr. Putin’s threat at the end of February: “We also have weapons that can strike targets on their territory,” the Russian leader said during his annual address. “Do they not understand this?”

The other answer lies in our recent history. When people around the world in the 1960s, ’70s, ’80s and early ’90s began to understand the nuclear peril of that era, a vocal constituency demanded — and achieved — change.

Fear of mutual annihilation last century spurred governments to work together to create a set of global agreements to lower the risk. Their efforts helped to end atmospheric testing of nuclear weapons, which, in certain cases, had poisoned people and the environment. Adversarial nations started talking to each other and, by doing so, helped avoid accidental use. Stockpiles were reduced. A vast majority of nations agreed to never build these weapons in the first place if the nations that had them worked in good faith toward their abolishment. That promise was not kept.

In 1982 as many as a million people descended on Central Park calling for the elimination of nuclear arms in the world. More recently, some isolated voices have tried to raise the alarm — Jamie Dimon, the chief executive of JPMorgan Chase, said last year that “the most serious thing facing mankind is nuclear proliferation” — but mostly such activism is inconceivable now. The once again growing threat of nuclear weapons is simply not part of the public conversation. And the world is less secure.

Today the nuclear safety net is threadbare. The good news is that it can be restitched. American leadership requires that Washington marshal international support for this mission — but it also requires leading by example. There are several actions that the U.S. president could take without buy-in from a Congress unlikely to cooperate.

As a first step, the United States could push to reinvigorate and establish with Russia and China, respectively, joint information and crisis control centers to ensure that misunderstandings and escalation don’t spiral. Such hotlines have all but gone dormant. The United States could also renounce the strategy of launching its nuclear weapons based only on a warning of an adversary’s launch, reducing the chance America could begin a nuclear war because of an accident, a human or mechanical failure or a simple misunderstanding. The United States could insist on robust controls for artificial intelligence in the launch processes of nuclear weapons.

Democracy rarely prevents war, but it can eventually serve as a check on it. Nuclear use has always been the exception: No scenario offers enough time for voters to weigh in on whether to deploy a nuclear weapon. Citizens, therefore, need to exert their influence well before the country finds itself in such a situation.

We should not allow the next generation to inherit a world more dangerous than the one we were given.

By W.J. Hennigan

Photographs by An-My Lê

This article was first published on March 7, 2024, before Joe Biden ended his campaign.

Forty-five underground in a command center near Omaha, there’s an encrypted communications line that goes directly to the American president. To get to it, you need to pass through a guarded turnstile, two reinforced steel doors and a twisting hallway that leads to an ultrasecure room called the battle deck. It’s here, below the headquarters of the U.S. Strategic Command, or Stratcom, where military personnel stand by 24 hours a day awaiting a call the world hopes will never come: a direct order from their commander in chief — the president — to launch a nuclear attack.

Stratcom is the military headquarters responsible for overseeing all U.S. nuclear forces around the world.

Buried below is a military command headquarters constructed in case of a missile attack amid a national emergency.

Inside this room, Stratcom’s commander, Gen. Anthony Cotton, and his team would speak directly to the president, informing him or her about the nuclear options during a continuing crisis.

The workstations in the battle deck are arranged stadium-style around 15 L.E.D. screens that glow with real-time information and maps. Hanging from the ceiling, a small digital display reads: Blue Impact Timer, Red Impact Timer and Safe Escape Timer, all set to 00:00:00. If a president were to order the launch of a nuclear weapon, the timers would start ticking, alerting everyone in the room to how long they have before American weapons hit the enemy, how long before the enemy’s weapons hit us and how long before the building and all the people in it are destroyed by the incoming nuclear-tipped missiles.

In the United States, it’s up to one person to decide whether the world becomes engulfed in nuclear war. Only the president has the authority to launch any of the roughly 3,700 nuclear weapons in the American stockpile, an arsenal capable of destroying all human life many times over. And that authority is absolute: No other person in the U.S. government serves as a check or balance once he or she decides to go nuclear. There is no requirement to consult Congress, to run the idea by the defense secretary or to ask the chairman of the Joint Chiefs of Staff for his or her opinion.

That means the American president is charged with the physical safety not only of some 334 million Americans but also of millions of people in other countries who, out of necessity, must rely upon his or her prudence and steady nerves to make a decision that could alter the course of human history.

Of course, it is American voters alone who will decide in November whom they want to endow with that power. The two front-runners — President Biden, who is 81, and former President Donald Trump, who is 77 — would be the oldest candidates in the nation’s history to appear on their parties’ tickets. Over the course of the year, they will have to confront questions from voters about their mental acuity, competence and stamina to take on another four-year term.

These are vital attributes for a commander in chief in a crisis. Yet regardless of who wins this election, or the next one, the American president’s nuclear sole authority is a product of another era and must be revisited in our new nuclear age.

No other aspect of U.S. military power is legally conducted this way. Authorizing drone strikes on terrorism suspects, for instance, requires approvals up and down the chain of command, from a commander in the field to the general overseeing the region to the defense secretary to the president. Larger operations, like a ground invasion of another country, require the president to ask Congress for a formal declaration of war or authorization for the use of military force.

Nuclear operations have a unique protocol. A nuclear attack against the United States could destroy the nation’s defenses and leadership in 30 minutes or less, giving the American president roughly 15 minutes to decide whether to launch a counterattack. The U.S. Strategic Command operates a global system to ensure that if a president orders the launch of a nuclear weapon, it will happen in minutes.

It’s an intricate procedure that involves dozens of people and perfect synchronization in a moment of inconceivable stress. Anyone in uniform who ignores a direct presidential order can be subject to court-martial for insubordination.

The E-6B Mercury is the airborne command post that links the U.S. president and U.S. military nuclear forces in the event of an enemy attack.

It’s code-named Looking Glass because it can mirror the command-and-control functions of Stratcom’s ground-based headquarters in Omaha.

The jet’s crew can contact the president, verify his or her identity and relay a nuclear attack order to bomber squadrons, submarines and intercontinental ballistic missile silos.

The idea that one human should have to make such a consequential decision in 15 minutes or less is nearly beyond comprehension. In reality, as long as nuclear weapons exist, there’s most likely no better option if the United States comes under attack. It is, however, unacceptable for an American president to have the sole authority to launch a nuclear first strike without a requirement for consultation or consensus.

Putting so much unchecked power in the hands of one person is not only risky but also deeply antithetical to how America defines itself. It also makes people deeply uneasy: Recent polling found that 61 percent of Americans are uncomfortable with the president’s sole authority. Over the years, several organizations have issued studies regarding the policy, providing recommendations on how it could be improved. Yet it survives.

One of the most surprising elements of the American president’s sole authority is how long this extraordinary power has lasted, rarely even challenged. It began in practice on August 10, 1945 — just days after the nuclear bombings of Hiroshima and Nagasaki — when President Harry Truman ordered that such action could not be taken without presidential permission. In September 1948, the Truman administration issued a memo that cemented the practice. Mr. Truman’s thinking was that nuclear weapons were too important to leave in the hands of military officers, who might be overly aggressive in the field.

Mr. Truman’s successors retained it in the Cold War years, when U.S. nuclear forces were on hair-trigger alert. From the 1950s through the 1980s, Washington’s biggest nightmare was a Soviet surprise attack that would obliterate U.S. fleets of bomber jets and ballistic missiles on the ground before they could be launched. The ability of a president to quickly launch a counterattack, unencumbered by the need for consultation, was considered vital to America’s survival.

Jake Sullivan, President Biden’s national security adviser, said his office is currently reviewing the policy and determining whether there’s sufficient oversight. Any changes would take place either through the exercise of presidential powers or action by Congress. “It is a complicated — and almost theological — issue,” Mr. Sullivan said. “We’re taking a look at it, but no decisions have been made.”

Previous efforts to change the law have gone nowhere. The first serious reconsideration came in 1976, when it became public that former President Richard Nixon was often drunk and depressed during the final days of his administration. A congressional committee convened to look into revising presidential launch authority for the pre-emptive first use of nuclear weapons, but four days of hearings did not result in legislative changes. The idea wasn’t revisited again until 2017, when Mr. Trump was in the White House and threatening military action against North Korea. Democrats in the House and Senate drafted a bill that would have required the president to obtain a congressional declaration of war before launching a nuclear first strike. It never went to a vote.

Senior officials in each of those administrations later revealed that they had been so concerned about the troubled mindset of their bosses that they tried to intercede by putting themselves in the chain of command if a launch order were given. In 1969, Henry Kissinger, national security adviser for Mr. Nixon, was reported to have stood down a drunken presidential order requesting recommendations for targets to strike in North Korea after it downed a U.S. spy plane. In 2021, Mr. Trump’s Joint Chiefs chairman, Gen. Mark Milley, told the speaker of the House, Nancy Pelosi, that the military would refuse to carry out a nuclear launch order if it was against the laws of armed conflict, according to “Peril” by Bob Woodward and Robert Costa. But legally, neither Kissinger nor Milley was part of the nuclear-launch chain of command, and it was therefore unclear what, if anything, they would have been able to do to stop a presidential order.

American military officers can choose to disobey orders they deem to be unlawful because they fail to meet the requirements under the law of armed conflict — if, for instance, the president ordered an unprovoked attack on a foreign country.

But even top officials have publicly admitted that it’s unclear how, exactly, a refusal to execute a presidential order might work. C. Robert Kehler, a retired Air Force general who once commanded Stratcom, tried to assure Congress in 2017 that internal checks are in place if a president orders an illegal first strike without prior deliberations and warnings. Kehler said he wouldn’t proceed if a president issued a direct order to execute such a launch. When asked what would happen next, he replied: “Well, as I say — I don't know exactly. Fortunately, we’ve never — these are all hypothetical scenarios.”

That’s not an uncertainty the world should have to live with. Congress should immediately establish a new legal framework that restricts the president from being able to issue a nuclear launch order without the consent of another senior official unless the United States is already under attack.

The legislation should identify two other senior government leaders and require at least one of them to concur with a decision to launch before the nuclear-tipped missiles blast off. These officials should be vetted and confirmed by the Senate as a requirement for their positions in the U.S. government — for example, the secretaries of defense and state, or the four-star general officer leading the Joint Chiefs of Staff.

Creating a deliberative process would help eliminate the possibility of an unhinged president recklessly instigating nuclear Armageddon, because of either madness or mishap. The policy change would also show our adversaries that the United States is lowering the risk of stumbling into a nuclear war by creating safeguards against an unfit U.S. commander in chief.

As the world staggers into another volatile nuclear age, Congress should not treat such scenarios as hypothetical. It should treat them as if all of our lives depend on them.

The president could order a partial or all-out attack drawing from the United States’ roughly 1,550 deployed strategic nuclear weapons, many of them magnitudes more powerful than the bomb dropped on Hiroshima.

The order is circulated to crews operating submarines, intercontinental ballistic missiles and bomber squadrons in the United States and under the sea.

They have less than 15 minutes before the adversary’s missiles reach the United States.

The fate of millions rests on the decision of one person.

W.J. Hennigan writes about national security issues for Opinion from Washington, D.C. He has reported from more than two dozen countries, covering war, the arms trade and the lives of U.S. service members.

An-My Lê’s 30-year body of work, which is inspired by her own experience of war and dislocation, is the subject of a retrospective at the Museum of Modern Art.

Produced by Quoctrung Bui, Jacqueline Bates and Jessia Ma; timeline analysis by Nuclear Threat Initiative.

This Times Opinion series is funded through philanthropic grants from the Carnegie Corporation of New York, Outrider Foundation and the Prospect Hill Foundation. Funders have no control over the selection or focus of articles or the editing process and do not review articles before publication. The Times retains full editorial control.

By Kathleen Kingsbury, W.J. Hennigan and Spencer Cohen
Photographs by Kentaro Takahashi

The waiting room of the Red Cross hospital in downtown Hiroshima is always crowded. Nearly every available seat is occupied, often by elderly people waiting for their names to be called. Many of these men and women don’t have typical medical histories, however. They are the surviving victims of the American atomic bomb attack 79 years ago.

Not many Americans have Aug. 6 circled on their calendars, but it’s a day that the Japanese can’t forget. Even now, the hospital continues to treat, on average, 180 survivors — known as hibakusha — of the blasts each day.

When the United States dropped an atomic weapon on Hiroshima on Aug. 6, 1945, the entire citizenries of both countries were working feverishly to win World War II. For most Americans, the bomb represented a path to victory after nearly four relentless years of battle and a technological advance that would cement the nation as a geopolitical superpower for generations. Our textbooks talk about the world’s first use of a nuclear weapon.

Many today in Hiroshima and Nagasaki, where the United States detonated a bomb just three days later, talk about how those horrible events must be the last uses of nuclear weapons.

The bombs killed an estimated 200,000 men, women and children and maimed countless more. In Hiroshima 50,000 of the city’s 76,000 buildings were completely destroyed. In Nagasaki nearly all homes within a mile and a half of the blast were wiped out. In both cities the bombs wrecked hospitals and schools. Urban infrastructure collapsed.

Americans didn’t dwell on the devastation. Here the bombings were hailed as necessary and heroic acts that brought the war to an end. In the days immediately after the nuclear blasts, the polling firm Gallup found that 85 percent of Americans approved of the decision to drop atomic bombs over Japan. Even decades later the narrative of military might — and American sacrifice — continued to reign.

For the 50th anniversary of the war’s end, the Smithsonian buckled to pressure from veterans and their families and scaled back a planned exhibition that would have offered a more nuanced portrait of the conflict, including questioning the morality of the bomb. The Senate even passed a resolution calling the Smithsonian exhibition “revisionist and offensive” and declared it must “avoid impugning the memory of those who gave their lives for freedom.”

In Japan, however, the hibakusha and their offspring have formed the backbone of atomic memory. Many see their life’s work as informing the wider world about what it’s like to carry the trauma, stigma and survivor’s guilt caused by the bombs, so that nuclear weapons may never be used again. Their urgency to do so has only increased in recent years. With an average age of 85, the hibakusha are dying by the hundreds each month — just as the world is entering a new nuclear age.

Countries like the United States, China and Russia are spending trillions of dollars to modernize their stockpiles. Many of the safeguards that once lowered nuclear risk are unraveling, and the diplomacy needed to restore them is not happening. The threat of another blast can’t be relegated to history.

And so, as another anniversary of Aug. 6 passes, it is necessary for Americans — and the globe, really — to listen to the stories of the few human beings who can still speak to the horror nuclear weapons can inflict before this approach is taken again.

***

A small pink booklet fits squarely in Shigeaki Mori’s breast pocket — a cherished possession that over the years has become more closely tied to his self-identity. The Atomic Bomb Survivor’s Health Handbook grants him access to free medical checkups and treatment, which at age 87 is critical. Flip open the first page to see his distance from the bomb when it detonated that bright August morning and flip another page to begin tracing years of his health history, written in neat rows of Japanese script.

Barack Obama was the first sitting U.S. president to visit Hiroshima, in 2016 — in sharp contrast to the regular visits of American leaders to Europe to commemorate major battles there. Mr. Mori was one of two survivors who spoke briefly with Mr. Obama after his remarks, leading to an emotional embrace between the two men.

On his living room wall, Mr. Mori proudly displays a photograph of that moment, alongside dozens of other mementos — including a photo with the pope — from his work over decades to remind the world of what happened in Hiroshima. Many Japanese hoped Mr. Obama’s visit would bring an official apology for the bombings; it did not. The president, however, did not shy away from recognizing the destruction of that day.

“We stand here, in the middle of this city, and force ourselves to imagine the moment the bomb fell. We force ourselves to feel the dread of children confused by what they see. We listen to a silent cry,” Mr. Obama said. “Mere words cannot give voice to such suffering, but we have a shared responsibility to look directly into the eye of history and ask what we must do differently to curb such suffering again.”

He recognized that voices like Mr. Mori’s are fleeting. “Someday the voices of the hibakusha will no longer be with us to bear witness,” Mr. Obama said. “But the memory of the morning of Aug. 6, 1945, must never fade. That memory allows us to fight complacency. It fuels our moral imagination. It allows us to change.”

The Smithsonian is in the midst of planning an exhibition on World War II, with a spotlight on the two bombed cities. It’s time for the next generation to bear witness and demand change.

Listen to Chieko Kiriake and Keiko Ogura tell their stories in an audio essay from Times Opinion.

Kathleen Kingsbury is the Opinion editor of The New York Times, overseeing the editorial board and the Opinion section. W.J. Hennigan writes about national security issues for Opinion from Washington, D.C. Spencer Cohen is an editorial assistant in Opinion. Ms. Kingsbury, Mr. Hennigan and Mr. Cohen spent a week in Japan reporting for Opinion’s series At the Brink, where they interviewed survivors, academics and other nuclear experts.

Kentaro Takahashi is a photographer based in Kyoto. Video by Rebecca Chew/The New York Times.

Interviews have been edited and condensed.

Source footage by Science Photo Library and Forrest Brown, via Getty Images.

This Times Opinion series is funded through philanthropic support from the Carnegie Corporation of New York, Outrider Foundation and the Prospect Hill Foundation. Funders have no control over the selection or focus of articles or the editing process and do not review articles before publication. The Times retains full editorial control.

By W.J. Hennigan
Photographs by An-My Lê

To understand how America is preparing for its nuclear future, follow Melissa Durkee’s fifth-grade students as they shuffle into Room 38 at Preston Veterans’ Memorial School in Preston, Conn. One by one, the children settle in for a six-week course taught by an atypical educator, the defense contractor General Dynamics.

“Does anyone know why we’re here?” a company representative asks. Adalie, 10, shoots her hand into the air. “Um, because you’re building submarines and you, like, need people, and you’re teaching us about it in case we’re interested in working there when we get older,” she ventures.

Adalie is correct. The U.S. Navy has put in an order for General Dynamics to produce 12 nuclear ballistic missile submarines by 2042 — a job that’s projected to cost $130 billion. The industry is struggling to find the tens of thousands of new workers it needs. For the past 18 months, the company has traveled to elementary schools across New England to educate children in the basics of submarine manufacturing and perhaps inspire a student or two to consider one day joining its shipyards.

The coursework — on this particular day, welding crackers together with Easy Cheese to create mini-submarines — is one small facet of the much bigger preparations America is making for a historic struggle with its nuclear rivals. With Russia at war, China escalating regional disputes and nations like North Korea and Iran expanding their nuclear programs, the United States is set to spend an estimated $1.7 trillion over 30 years to revamp its own arsenal.

The spending spree, which the government began planning in 2010, is underway in at least 23 states — nearly 50 if you include subcontractors. It follows a decades-long freeze on designing, building or testing new nuclear weapons. Along with the subs, the military is paying for a new fleet of bomber jets, land-based missiles and thermonuclear warheads. Tally all that spending, and the bill comes to almost $57 billion a year, or $108,000 per minute for three decades.

Times Opinion spent six months traveling to cities and towns around the nation to discover how this modern Manhattan Project is coming together, interviewing more than 100 residents, workers, community leaders and federal officials. The portrait that emerged is a country that is being transformed — physically, financially and philosophically — by an unprecedented wave of nuclear revitalization. The effort is as flush with cash as it is rife with problems and delays: At least 20 major projects are already years behind schedule and billions of dollars over budget.

If you don’t live where the submarines are welded or the missile silos are dug, there’s a good chance you wouldn’t know it’s happening. The federal government has said little about the plan in public, outside of congressional hearings and strategy papers, or the vast amount being spent. There has been no significant debate. The billion-dollar programs move under the radar. At a time when funding for politicized issues such as climate change, foreign military aid and border security are under a microscope, this issue miraculously appears to have sidestepped the crossfire.

But each day, more than 110,000 scientists, military personnel and private contractors with high-level security clearances are scanning into facilities, putting on safety gear and piecing together a modern arsenal for a volatile new nuclear age.

We should talk about why Washington is making America nuclear again and what we hope to achieve with one of the most ambitious, far-reaching construction projects in the country’s history. The money is already flowing, assembling weapons everyone hopes will never be used.

General Dynamics Electric Boat may face a labor shortage, but you wouldn’t know it standing inside one of the company’s football-field-size warehouses along Narragansett Bay in Rhode Island.

On a morning in September, roughly 2,000 employees were at work across the sprawling complex, moving among mammoth machinery and the hulls of several submarines sliced into segments like giant sushi rolls. “What you’re seeing is the future of American naval power,” Rear Adm. Todd Weeks, who oversees strategic submarine construction for the U.S. Navy, shouted above the din.

At 560 feet long and 43 feet in diameter, the Columbia-class submarines under construction at the site will be the largest America has ever built when the first boat enters service this decade. They are also the most expensive, at an average of $11 billion per boat. Engineering a nuclear submarine is widely considered to be more challenging than building a spacecraft: The sub needs to carry more than 100 people to crushing ocean depths, along with the nuclear reactor that powers it, and be capable of launching its nuclear-tipped missiles to any location on the planet. Every cut, every weld, every rivet matters.

On the factory floor, it is plain to see the dream of nuclear disarmament, once shared by Republican and Democratic presidents alike, is dead. Or, at the very least, on life support. Not so long ago, the consensus among global leaders was that the world needed fewer nukes and means to deliver them, not more. America’s nuclear portfolio was deprioritized after 1991, when the Soviet Union collapsed. After spending trillions of dollars over decades, Washington cut back on nearly everything nuclear-related. The prongs of the American military’s so-called triad — nuclear-weapon-carrying submarines, jets and intercontinental ballistic missiles — were maintained, rather than replaced, for years beyond their intended use.

Nuclear ballistic missile submarines — known as boomers by sailors — are arguably the most important part of that ecosystem. They are America’s guarantee that the military can strike back in the event of the country incurring a first attack, even if an adversary manages to turn Washington into radioactive ash. They are constantly deployed around the world, are virtually undetectable under the water and can carry up to 20 long-range missiles loaded with several nuclear warheads apiece.

The 14 boomers now at sea are about 40 years old, on average — ancient in submarine years. The aging boats come with a host of liabilities, including higher maintenance costs and onboard technology that predates the personal computer revolution. With China operating the world’s largest, newest naval force (234 warships to America’s 219), the U.S. Navy says new submarines can’t be produced fast enough. Once U.S. production hits its stride, the plan is to build one boomer and two attack submarines a year. To make that happen, the Quonset Point factory has added six buildings, doubling its floor space, from one million square feet to two million square feet, over the past 10 years.

But four years in, the first boat is hundreds of millions of dollars over budget because of a combination of supply chain issues, design problems and nagging labor shortages. Recent analysis from the Government Accountability Office, the congressional watchdog, calculated cost overruns that are more than six times the company’s estimates.

When the Cold War ended, the demand for subs dropped, and the pipeline of trade specialists trained to work on these highly specialized boats did, too. General Dynamics Electric Boat’s work force sank from around 22,000 to 7,000. The Navy now estimates it needs at least 100,000 new workers to join defense companies to meet production demands.

Though the new Columbia-class subs are primarily being built in Rhode Island, Connecticut and Virginia, the Navy is going to tremendous lengths to recruit talent across the country. Over the past year, a blitz of ads has appeared at various sports events — including major league baseball games, WNBA games and even atop a NASCAR hood — steering fans to buildsubmarines.com. The website connects job seekers with hiring defense contractors as part of a nearly $1 billion campaign. Some of that money will go toward helping restore the network of companies that can supply the more than three million parts that go into a Columbia sub. Like so much of the nation’s nuclear infrastructure, those supplier numbers have plummeted since the 1990s.

Arms control advocates argue that the U.S. industrial buildup risks igniting another arms race. But to hear Admiral Weeks tell it, the Navy is well beyond such hand-wringing, thanks in part to Russia and China: “As we see the world today, that dip that we had in the late 1990s, early 2000s — we don’t see that happening again.”

Any passing driver can watch the construction on the industrial park along Bear Creek Road in Oak Ridge, a city in the far eastern corner of Tennessee. Crowds of laborers move among four unfinished buildings, heavy machinery growling at the edges. It looks like any other work site, until you notice the tiers of razor wire, patrols of armed guards around the perimeter and the peculiar fact that none of the structures have any windows.

This construction site, for the Y-12 National Security Complex, is the top-secret centerpiece of America’s plans to rebuild the nation’s nuclear bomb-making complex. When the $10 billion overhaul is done, the revamped site will be solely responsible for processing the highly enriched uranium used in U.S. weapons into the next century. But if you keep driving down the road, it feels as though you’re moving back in time. Row after row of aging brick buildings are scattered across Y-12’s campus, many containing hazardous waste that dates back decades.

After World War II and the start of the Cold War arms race, manufacturing uranium components for nuclear weapons became the site’s defining mission. Every nuclear weapon in America’s current arsenal of 3,748 nuclear bombs and warheads contains uranium from Y-12.

The Energy Department, which oversees the nuclear stockpile, went through an extensive retrenchment after the U.S.S.R. collapsed, much like the military. The overall number of weapons was cut. The budgets of the labs that designed the weapons were cut. The skilled work force that manufactured and assembled them was cut. The facilities where this work took place, full of modern equipment during the Cold War, were never updated.

Few, if any, sites embody this neglect better than Y-12. Despite all the technological advancements that have unfolded outside Y-12’s barbed wire fences over the past 80 years, America’s nuclear arsenal is still largely put together there by hand, like a Ferrari engine, using machines created decades before their operators were born.

Signs of decay and decrepitude are everywhere. Eric Helms, the deputy director of enriched uranium operations, who has worked at Y-12 for 23 years, leads me through a labyrinth inside the complex of narrow hallways in Building 9212, where workers stand in coveralls. Strips of the ceiling hang overhead like ribbons. Sections of pipe that jut from the hulking machinery are wrapped with duct tape, and paint on the steel doors and walls has chipped away, exposing layers of green, brown and cream underneath. “That’s where we painted over contamination spills,” he says. “Stripping the paint would just create a bigger problem.”

Large areas of the floors have also been painted over or feature a patchwork of stainless steel sheeting to cover contaminated concrete below. On the day I visit, the internal 1950s-era vacuum system has been broken for more than a week, so workers can’t suck away scraps of uranium that fell around the furnaces. Mr. Helms says it’s a nagging problem. “We’re looking forward to moving into the new facility,” he says.

Today Y-12 is under the control of the National Nuclear Security Administration, a quasi-independent arm of the Energy Department. Once the new facility is up and running, it will process uranium not only for nuclear weapons but also for the nuclear reactors aboard U.S. Navy ships and nuclear research reactors. Much of the radioactive material will be shipped by truck to the National Nuclear Security Administration’s Pantex plant in Texas, where it will be assembled into different types of nuclear warheads. The surplus will be held in an onsite storage vault nicknamed the Fort Knox of uranium.

For that, Mr. Helms and the rest of the staff will have to wait. Six years into its renovation, construction at Y-12 is years behind schedule and around $4 billion over budget because of a combination of supply chain hiccups and unforced errors. (At one point, a contractor mistakenly designed the roof 13 feet lower than it needed to be in the new uranium-processing building, costing $540 million alone.)

Because of the repeated delays, the earliest that Mr. Helms and his team can move into the new facilities is 2031.

Unlike most of the U.S. military’s weapons systems, America’s intercontinental ballistic missiles, which ferry nuclear warheads to their target, aren’t kept on military bases or in warehouses. Currently, 400 Minuteman III missiles are buried 80 feet underground in people’s backyards — or, more specifically, their farm fields — in Wyoming, Nebraska, Colorado, Montana and North Dakota.

For decades, these aging missile systems have been on 24-hour alert, ready to obliterate almost any spot on Earth using the best technology available in the 1970s, when they were installed. The Air Force, which is in charge of the land-based missiles, has been maintaining the missiles for half a century.

Now the entire system is set to be replaced. Changing out the missiles, silos, command hubs and roughly 7,500 miles of underground cables snaking under the property of thousands of landowners will be one of the most expensive projects in military history, rivaled only in scale and technical complexity by the operation to build the Interstate System of highways.

For the past two years, representatives of the Air Force have fanned out across the northern Great Plains to talk to residents about the plans. Construction crews have begun work on support buildings at F.E. Warren Air Force Base in Wyoming. The hope is to open new silos through the next two decades — but the project could go well beyond that, given the current delays — and steadily bring the Sentinel system online while maintaining the old Minuteman III system until it’s fully replaced. Up to 3,000 laborers will descend on dozens of small towns to live in temporary camps, potentially doubling or tripling the local populations for however long they need to be there.

The Air Force does not yet know how or where the workers will be housed, which is a concern for some people living in these missile-hosting towns, many of which have only one or two law enforcement officers. Robin Darnall, a commissioner for Banner County in western Nebraska, says she’s focused on how to balance the influx of workers along with the safety of farming and ranching families, whose forebears, in some cases, arrived there in homesteading days. “I feel like we need to increase our law enforcement in Banner County for this project,” she says. “Our sheriff can’t do that all and satisfy his current responsibilities.”

When the Air Force installed missiles there in the 1960s, locals enthusiastically embraced the idea of providing a home to a critical national security project aimed at defeating the Soviets. The arms race was on, after all. But today, like in most of America, the grave threat of nuclear war barely registers to many residents of the heartland, even if classified work is happening beneath the communities they live in.

In the Great Plains, too, things are taking longer than they should. The missile modernization program, called LGM-35A Sentinel, was first estimated to cost about $96 billion in 2020, when the defense company Northrop Grumman won the initial contract to build the system. The price tag has since skyrocketed, with current costs pegged at around $141 billion, a cost increase so severe that it triggered the Nunn-McCurdy Act, which requires the Pentagon and Congress to evaluate whether to cancel troubled programs. The government is reviewing the details but has already decided to move forward with building the new missiles.

Walter Schweitzer passes a missile silo almost every day on his way to work as president of the Montana Farmers Union. He and his members are military supporters but are increasingly concerned with the lack of information provided by the Air Force. Another point of contention involves restrictions around the silos, such as forbidding wind farms within a two-mile radius. “Unless you’re prepared to reimburse property owners the loss of their rights, then the farmers’ union can’t support that,” Mr. Schweitzer says. “No way. No how.”

Outside the lab, the scenic town of Los Alamos, N.M., is being renovated with all manner of construction projects to accommodate the new arrivals. Inside the lab, technicians and scientists are busily melting, refining and shaping plutonium into grapefruit-size cores that trigger the explosions in nuclear bombs.

Manufacturing plutonium pits, which is what the nuclear industry calls them, can be a messy and dangerous business. The radioactive metal has to be shaped into hollow spheres. Workers do this by handling it with rubber gloves inside workstations called glove boxes. It takes skill and nearly a year of training to become comfortable working with such perilous material. A tiny shaving of plutonium can kill a person if it is inhaled. Accounting for every bit of it is crucial.

In 2018, Congress directed Los Alamos, which is overseen by the National Nuclear Security Administration, to produce 30 plutonium pits a year by 2026. The agency plans to manufacture an additional 50 pits a year at a larger facility in Savannah River, S.C. The pits will go into the warheads that are affixed to the new Sentinel missiles.

Some progress is being made: On Oct. 1, Los Alamos produced the first pit certified to enter the war reserve. But meeting the full production mark won’t happen until the mid-2030s, at the earliest, the National Nuclear Security Administration says, as the cost estimate has climbed to more than $28 billion. The upside is the delays won’t hurt as much because everything is behind schedule, including the missiles.

The last time the United States was mass-producing plutonium pits, it didn’t go well. The Rocky Flats production site in Colorado was the last place to do it. In 1989 the facility, overseen by the Energy Department, was raided by the F.B.I. and Environmental Protection Agency and later shut down after rampant environmental violations were discovered. It was a rare episode in U.S. history in which one federal agency raided another.

The output at Rocky Flats, which at one point during the Cold War hit 1,000 pits per year, dwarfs the modern ambitions of Los Alamos. Still, the new production is expected to generate levels of radiological and hazardous waste that the lab has not experienced. This comes on top of the contamination already present, which the government estimates will cost some $7 billion to clean up. “We’re endangering our community for an unnecessary arms race that puts us all at risk,” says Jay Coghlan, the executive director of Nuclear Watch New Mexico, a Santa Fe-based watchdog.

Environmental contamination isn’t the only concern that Los Alamos’s neighbors have. The Los Alamos County Council recently passed a $377 million budget for fiscal year 2025 — an eye-popping sum for a population of just 19,400. County officials say their primary focus is housing and amenities. The lab hired 4,000 employees over the past two years, and it’s been a struggle to find homes for them all. A recent study found they have a housing shortfall of at least 1,300 units, which county officials attribute largely to the lab expansion.

Los Alamos’s strategic location, nestled between canyons, poses a vexing challenge. The limited space creates transportation problems in and out of the town, which has led to a spate of auto accidents, including one in September in which a former lab director, Charles McMillan, was killed. To alleviate traffic, money is also going into infrastructure improvements and an expansion of the Atomic City Transit system.

“Our whole community has changed with this new bomb factory,” says Greg Mello, the executive director at the Los Alamos Study Group, a nonprofit watchdog that is critical of the nuclear weapons complex’s expansion. “There’s no telling where it will end.”

Last century, the world watched in horror as the number of nuclear weapons around the globe rocketed from approximately 3,000 warheads in 1955 to more than 70,000 by the late 1980s. It took time for nuclear nations to grasp the mutual vulnerability, the financial investment and general insanity of the arms race. Cooler heads prevailed. International treaties were signed. Now there are an estimated 12,000 nuclear weapons in the world.

All of the progress meticulously made over the past 40 years is now at risk. Agreements are being abandoned rather than forged. The future of arms control appears bleak. The United States is considering increasing the number of weapons in its arsenal — not just replacing the old ones — after the New Start Treaty with Russia expires in February 2026. If such a decision is made, foreign adversaries will certainly follow suit.

After all, decisions about an arsenal in one nation trigger rethinking among them all. Since the United States first took concrete steps toward rebuilding its weapons in 2010, the eight other nuclear-armed nations are believed to have expanded or enhanced theirs. Russia has overhauled its nuclear arsenal. China is on track to double the number of its nuclear warheads by the decade’s end and may continue building, according to U.S. intelligence estimates.

It is undeniably true that the world is becoming more contentious, and nuclear weapons do deter our adversaries. But it’s also true that our children will inherit this — the nationwide nuclear complex revitalization, the astronomical bill, the potential for confrontation. Congress decided that America needed new weapons when it first allocated funding to their replacement more than a decade ago. But it’s clear, after I visited these places, that the American people have not. Even in communities where this work is happening, there is too little awareness about what’s occurring, let alone in the rest of the country.

Our next president will have to decide whether America needs these new weapons. Americans deserve to know more about the candidates’ views, how our money is being spent and what’s at stake. After all, the weapons under development using taxpayer dollars are expected to be with us well into the next century. And if any one of them were ever used, it would fundamentally change the course of human history.

So should Americans brace for another arms race? Another Cold War? To put it in perspective: The Manhattan Project cost about $30 billion, adjusted for inflation, over the course of World War II. The United States is on pace to spend nearly double that amount each year for at least 30 years. It’s time to reflect on whether we are on a path toward a brighter future or headed back to a darker past.

W.J. Hennigan writes about national security issues for Opinion from Washington, D.C. He has reported from more than two dozen countries, covering war, the arms trade and the lives of U.S. service members. Additional reporting by Spencer Cohen.

An-My Lê, whose work exploring themes of displacement and war was the subject of a retrospective at the Museum of Modern Art, is an arts professor at Bard College.

This Times Opinion series is funded through philanthropic support from the Carnegie Corporation of New York, Outrider Foundation and the Prospect Hill Foundation. Funders have no control over the selection or focus of articles or the editing process and do not review articles before publication. The Times retains full editorial control.

By W.J. Hennigan
Graphics by Taylor Maggiacomo and Jeremy Ashkenas

U.S. military personnel at Space Command, in Colorado Springs, have kept a close eye on Cosmos 2553 ever since it reached orbit. Bathed in the bluish glow of their computer screens, they sit and watch what’s going across all of space day after day, tracking the latest information on satellite constellations, coming rocket launches and the daily operation of the space-based systems that shape modern life.

But Cosmos 2553 is different. It circles Earth every two hours in a region called a graveyard orbit. Only 10 other satellites are out there, and all of them have been dead for years. The area is rarely used in part because it’s inside the Van Allen belts, zones of high radiation that encircle the planet.

That’s why Moscow claims Cosmos 2553 is there — to test out “newly developed onboard instruments and systems” against radiation. But what it’s really doing, U.S. officials say, is testing components for a Russian weapon under development that could obliterate hundreds, if not thousands, of critical satellites. Cosmos 2553 isn’t armed, but it does carry a dummy warhead, one of several details being reported here for the first time. So while the orbiting satellite poses no imminent danger, the officials caution it does serve as a forerunner to an unprecedented weapon.

Although they are almost invisible in our day-to-day lives, satellites increasingly control how we live. Everything from pumping gas to trading stocks to checking tomorrow’s weather forecast depends on satellite signals, and the world’s collective appetite for these systems is growing. More satellites have been launched into orbit in the past five years than in the previous six decades as commercial companies and governments spend billions to build new constellations for communications, Earth imagery and other services. Most of them travel around Earth in a part of space called low-Earth orbit, an area within 1,200 miles of the planet.

U.S. intelligence analysts haven’t determined if it’s this region or some other area that Russia may one day threaten if it ever deployed such a device. In any scenario, a nuclear weapon detonated in outer space wouldn’t have a localized impact like a direct hit with a missile strike. It would be indiscriminate, affecting all nations. If the Kremlin decided to use a Sput-nuke, as the device is sometimes derisively called, it holds the unambiguous potential to disrupt the future of America’s military space operations and the lives of hundreds of millions of civilians around the globe.

Once considered a largely peaceful domain, space is now viewed by many American lawmakers and military commanders as a place where the next major global conflict might unfold. If Moscow is working on a space nuke, it would be merely one of dozens of space weapons under development or already in use by Russia, China and the United States. All three nations have tested high-flying missiles capable of targeting space systems from the surface and have lasers, signal jammers and other devices that can disrupt space operations. Russia has deployed nesting doll satellites (in which one satellite births a smaller satellite that is maneuverable and armed with a projectile) and China and the United States have demonstrated grappling satellites, which can sidle up to another satellite and tug it out of its orbit with robotic arms.

It may sound as if these technologies were torn from the pages of a science fiction novel, but none of them come close to doing what a nuclear weapon could in space: wipe out clusters of satellites at once.

As the risk of conflict in space climbs, there are surprisingly few international agreements to safeguard against military action there — and no established norms. There are just two major pacts governing nuclear weapons in the cosmos, both of which predate Neil Armstrong’s first steps on the moon. The Limited Test Ban Treaty, which prohibits nuclear tests in the atmosphere, underwater or space, was signed by the United States, Britain and the Soviet Union in 1963. The Outer Space Treaty, which was first signed less than four years later, bans deploying “nuclear weapons or any other kinds of weapons of mass destruction” in orbit. Today, both decades-old agreements are proving shaky. With a new generation of weapons under development, space experts see a rising potential for miscalculation, misinterpretation and aggression.

While the American government says it has tracked Russia’s nuclear anti-satellite program for nearly a decade, it’s impossible to independently verify its claims about Cosmos 2553. But even the prospect of such a device should alarm the more than 90 nations with at least one satellite in orbit. The potential threat to the world’s satellites may emanate from Russia today, but it doesn’t end there. Any nation with ballistic missiles and nuclear weapons, like North Korea, holds the potential to reverse the progress of the space age with a single detonation.

It is a development that the world must not look on with indifference. In his first administration, Donald Trump created the Space Force, a clear indication that he recognizes the threat of the mounting militarization and weaponization in outer space. In his second term, it’s imperative for Mr. Trump to lead an international effort that aims to improve space traffic management, open new communication channels with adversaries and slow the rapid development of space weapons that is already underway.

We rely on space more than ever

Perhaps the easiest way to understand the extent of our reliance on space is gazing upon the night sky. It doesn’t take long before Starlink satellites come into view, streaking among the celestial bodies. With around 6,500 active satellites, Starlink, operated by Elon Musk’s SpaceX, accounts for more than half of the world’s inventory. Starlink provides high-speed internet to customers who purchase terminals and is accessible almost anywhere on the planet, including Ukraine, where it has proved crucial to Ukrainian troops on the battlefield. (Moscow has since said any company that provides satellite service to Kyiv’s forces could become a target.)

SpaceX has plans to greatly increase the size of its constellation in the coming years. That’s a lot on its own, but Amazon also has plans to build a system to compete with Starlink in the next few years. China hopes to launch 40,000 of its own such satellites in the next decade, and the Pentagon is set to spend nearly $14 billion over the next five years to build its new system of missile-targeting satellites in low-Earth orbit. All told, the global space economy is expected to grow to $1.8 trillion by 2035, roughly three times where it stood in 2023, according to a recent industry analysis.

It’s hard to overstate modern armed forces’ reliance on space. They use it to drop bombs on targets, communicate, navigate and track potential incoming attacks. When Iran launched around 200 ballistic missiles toward Israel in early October, for instance, U.S. forces knew well in advance where many of the missiles were positioned, the split second they launched and the approximate locations they were on course to hit. That so few of those missiles got near their targets is proof of the extraordinary technological advantage of America and its allies in space. This dominance is also an Achilles’ heel. U.S. military analysts believe the dependence on such systems is seen as a wartime vulnerability by our adversaries, including China and Russia.

Taking out these satellites, particularly in a conflict, could even the playing field. The conventional anti-satellite weapons that Beijing and Moscow have developed could render orbiting satellites useless. The United States responded to this growing threat by launching a satellite constellation last year code-named Silent Barker to monitor its spacecraft, and the Space Force continues to enhance its ability to fend off potential attacks.

The discovery of Cosmos 2553 has generated serious contemplation at the highest levels in Washington about the worst-case scenario, including examining military policies and considering whether to entrust military commanders with more options and tools for conducting conventional counterattacks.

What if a nuclear weapon detonated in space?

If a war in space is difficult to fathom, a nuclear detonation is unthinkable. The devastation would be counted not in casualties but in mass disruption to our everyday lives, from vital services like weather forecasting and navigation to supply chains. Many of the larger national security satellites — comparable in size to school buses — are much farther from Earth, in what’s called geostationary orbit, and contain electronics designed to withstand radiation from a nuclear detonation. But thousands of satellites in low-Earth orbit have little to no protection and are profoundly vulnerable to such an attack.

Much of what we know about the effects of nuclear weapons in space stems from two series of U.S. tests conducted during the Cold War, code-named Operation Argus and Operation Fishbowl.

One test in 1962, called Starfish Prime, knocked out a third of the two dozen satellites in orbit at that time.

Here’s what would happen if a weapon detonated near low-Earth orbit today.

There would be no sound, no fire and no shockwave. There would be no mushroom cloud.

From the surface, people would see a brilliant light, followed by dazzling auroras generated by a burst of electrons colliding with gases in the atmosphere.

The detonation would disable and destroy everything in its immediate vicinity, turning satellites into unguided projectiles that could crash into one another.

Objects in low orbits travel at around 17,000 miles per hour. Any debris — even as small and light as a paint chip — would pose real danger to other objects or people in space.

Meanwhile, the burst of intense radiation produced by the detonation would be captured by Earth’s magnetic field.

Swirling away from the blast point, the charged particles would form a shell of radiation that would linger for weeks, if not years — long enough to gradually fry the onboard electronics of surviving satellites orbiting close to Earth.

U.S. intelligence analysts have determined low-Earth orbit would be unusable for an unknown period, depending on the size of the blast.

Predictions about how an event like a nuclear detonation in space would affect human life are difficult to pin down. Any astronauts aboard the International Space Station would likely face grave danger and future human spaceflight would be imperiled for some time. A U.S. National Intelligence Council analysis of the possible economic damage caused by a nuclear blast in low-Earth orbit warned that there would be a widespread impact on travel and shipping, banking and financial markets, the oil and gas industries and farming and supply chains.

Even a detonation closer to Earth could have catastrophic effects. Such a blast high above a major city may not harm the population, but the bomb’s electromagnetic pulse could cause crippling blackouts and permanently damage electrical grids. The Soviets demonstrated these effects during a series of nuclear tests, code-named the K Project, in the early 1960s.

U.S. intelligence had been tracking Russia’s interest in developing a nuclear anti-satellite weapon years before Cosmos launched in 2022, officials say. Once they detected it, just weeks before Russia invaded Ukraine, military officials at Space Command’s Joint Operations Center in Colorado Springs started to pull together information from various intelligence agencies. They keyed satellite sensors onto the Cosmos 2553 and told leaders at the Pentagon what they believed they had found: a working model for Russia’s nuclear anti-satellite program that relays data on how an operational weapon would perform, should it be placed in orbit.

All this was kept in tight secrecy until last Feb. 14, when Michael R. Turner, an Ohio Republican who is the chairman of the House Intelligence Committee, put out a cryptic statement calling for the release of classified material about a “serious national security threat.” As more information trickled out of Washington about the potential weapon, President Vladimir Putin of Russia publicly dismissed the allegation. “Our position is clear and transparent: We have always been categorically against and are now against the placement of nuclear weapons in space,” he said. The Russian Embassy in Washington did not respond to a request for comment.

Although the Soviet Union, now Russia, signed the 1967 Outer Space Treaty, which forbids nuclear weapons and other weapons of mass destruction in space, that’s not exactly easing anyone’s mind. At the United Nations in April, Russia vetoed a resolution that reaffirmed provisions in that treaty. And in recent years, both Russia and the United States have walked away from several Cold War arms agreements as relations between the countries have worsened.

There are also several United Nations agreements ‌that regulate various aspects of outer space, but space-faring countries have yet to solidify norms and conventions for responsible actions in orbit. How close can one nation’s satellite approach another nation’s satellite? When they inadvertently draw close, which way should they turn to avoid crashing? How should satellite operators communicate with one another? It took centuries in maritime and decades in aviation law to establish such rules and identify safe and professional behavior. It’s now time for outer space.

Although U.S. administrations including President Biden’s have tried to move the world closer to a consensus on the rules of the road, progress has been slow. One hundred and fifty-five states, including the United States, voted in favor of a United Nations resolution calling to halt debris-generating anti-satellite missile tests from Earth, but Russia and China voted against the measure. After Russia vetoed the reaffirmation of the Outer Space Treaty, Moscow, along with Beijing, introduced a competing resolution calling for a ban on the placement of all weapons in outer space. That also failed after the United States and other nations dismissed it as a ploy to distract attention from its true intentions.

Therein lies the challenge. The United States, Russia and China are growing further apart rather than coming together to forge such agreements. Verifying that a satellite isn’t carrying a nuclear weapon or some other harmful payload becomes even more difficult once it’s put into orbit. And writing legal definitions of what qualifies as a space weapon is a formidable task because of dual-use capabilities. A grappling satellite, for instance, that does the necessary work of grabbing and pulling dead satellites from orbit could also in theory be used to remove another nation’s functioning national security satellite from its position, though no nation is known to have done so to date.

There are clear points where collaboration can still happen that would benefit all countries — and provide the foundation for future agreement. A United Nations report in May noted the growing congestion in low-Earth orbit and urged states to consider an international framework for nations to share information on satellites and space debris. It echoes a topic already under discussion in Washington about developing an effective channel with Moscow and Beijing to coordinate space traffic. Such a safety mechanism could prove useful, particularly during a diplomatic or military crisis, to avoid an honest mistake like an unintended collision being interpreted as an act of war.

The U.S. military is on board for this kind of open channel, beyond the limited ones in operation now. “We want to have a way to deconflict and have space safety discussions, which would enable those tenets of responsible behavior,” said Gen. Stephen N. Whiting, who oversees Space Command.

American leadership is needed to bring other nations into the hotline and to maintain peace — however uneasy — in space. When news of Russia’s nuclear anti-satellite program became public, Secretary of State Antony Blinken reached out to his counterparts in India and China to help apply pressure on Moscow about the program. Mr. Trump should try to expand on that effort when he re-enters the White House. Rather than fuel an accelerated space arms buildup, he should instruct his National Security Council to mobilize a diplomacy-led, multilateral effort to draw up rules of behavior in outer space that reflect the technological reality of today.

A good start would be for Mr. Trump to call out Cosmos 2553 by name — something the Biden administration hasn’t publicly done — and further express the need to build on the half-century-old Outer Space Treaty with China and Russia. The president-elect might opt to consult Mr. Musk, who as founder of SpaceX has much to lose with a military confrontation in space. As he no doubt knows, the world has spent decades delicately constructing the space architecture that enables our daily life. Any act of war in space, much less a nuclear detonation, would needlessly put all that at risk.

History has shown that wherever there’s a potential for financial or strategic advantage — on land, in the air or at sea — it’s accompanied by the prospect of war. The peril now looms above us, and it can no longer be overlooked.

W.J. Hennigan writes about national security issues for Opinion from Washington. He has reported from more than two dozen countries, covering war, the arms trade and the lives of U.S. service members.

This Times Opinion series is funded through philanthropic support from the Carnegie Corporation of New York, Outrider Foundation and the Prospect Hill Foundation. Funders have no control over the selection or focus of articles or the editing process and do not review articles before publication. The Times retains full editorial control.

Note: Satellites, launch path and detonation in opening animation are for display purposes only.

Additional production by Gus Wezerek. Additional reporting by Spencer Cohen.