In the eighty years since the first successful test of a nuclear weapon, generations of effort has been spent to limit the spread of these weapons and prevent their use. The Federation of American Scientists, since our founding in 1945, has played a central role in helping understand the dangers posed by nuclear weapons and diligently worked to ensure the policy debate is informed by scientific and technical data. As part of our continuing legacy, the Global Risk program at FAS partnered with the Washington Post to publish a five part opinion series entitled: The Next Nuclear Age. 

With 2000 nuclear weapons on alert, far more powerful than the first bomb tested in the Jornada Del Muerto during the Trinity Test 80 years ago, our world has been fundamentally altered. This series resurfaces clear warnings that nuclear policy is not just a relic of days gone past. Past generations had this threat at the forefront of their minds as a clear and present danger to the future civilization. However distant 80 years may feel, the threat still reaches into contemporary times with most recently the nuclear program of Iran becoming the target of strikes by the U.S. Military. 

The Iran strikes are the manifestation of a debate mostly relegated to non-proliferation policy circles. We can watch as the preemptive effort to halt progress of Iran’s nuclear weapons program plays out in press conferences and analysis rather than the hypothetical. The strikes on Iran offer a unique pivot to evaluate some of the underlying assumptions about deterrence and what role the U.S. is willing to play in international institutions with our allies. There has been much analysis of the Iran strikes framed using the traditional logic of being able to halt programmatic development through brute force, i.e. bomb enrichment sites. In my assessment, more progress has been made and could continue to be made by supporting the sanctions regime and using more social coercion by partnering with our allies and supporting international institutions. When we choose to use military force, we ultimately trade in our legitimacy in the rules based order, pushing our allies to look at building their own nukes for security.  

The real world implications of nuclear policy and diplomacy can be seen in the unfolding story with Iran, which is not quite done yet. The Next Nuclear Age as a five part series surfaces and grapples with the realities of living in the nuclear age and dispels myths surrounding nuclear policy and non-proliferation. Each part paints a vivid picture that reviews the history of nuclear close calls and details how the long-standing norm against proliferation is eroding. The subsequent articles describe how a nuclear war could start, who controls the use of nuclear weapons in the United States, and how a nuclear attack could unfold in the United States.     

In the post Cold War Era, nuclear weapons have largely faded from the heat of popular culture however their threat is still a sobering reality. The Next Nuclear Age series serves as a reminder that the durability of the nuclear threat is omnipresent in modern life. Thousands of weapons are aimed and on high alert, one person has sole authority to launch, and a growing number of nations are considering spending billions to secure nuclear options as tensions rise.   

After decades of work trying to reduce the threat of nuclear weapons, our days ahead look riskier than in years prior. The multipolar geopolitical landscape exponentially raises risks of accidents and increases excuses to jump into an arms race. Countries are falsely substituting military capability for political credibility therefore increasing risk. Our allies and institutions are being clobbered by disinformation and mistrust and we are left feeling the pinch, having to result in widely unpopular military interventions in potentially protracted conflicts. 

This series showcases how the accidents, miscalculations, and escalatory spirals have more room to become trigger points. Compressed decision-making timeframes revealed in the final installment show how quickly rational deliberation can give way to existential pressure. What worries me is that we’ve given up tools in our tool box that monitor and reduce risk. We’ve traded out diplomatic solutions and investment for military build up and an expensive vanity project of Trump’s Golden Dome. Ultimately it is our responsibility as citizens to uphold policymakers to account on these weapons before the unthinkable becomes inevitable. 

Part 1:  Why we should worry about nuclear weapons again

The Cold War prospect of global annihilation has faded from consciousness, but the warheads remain.

By Jon B. Wolfsthal, Hans Kristensen and Matt Korda

The threat of nuclear weapons since the collapse of the Soviet Union has been largely absent from the public’s consciousness. Stockpiles have been reduced from Cold War highs but the thousands of  remaining weapons could still destroy humanity.  

“It is as if the lessons of the Cold War — that there is never a finish line to the arms race and that more effective nuclear weapons do not lead to stability and security — have been forgotten by the current generation of defense planners.” 

The new frame of great power competition among the US, Russia and China, plus new nuclear dangers make today’s nuclear age more complicated and dangerous than the nuclear standoff between the first two major powers of the late 20th century. Nuclear policy experts refer to the U.S.-Russia-China nuclear triangle as a ‘three body problem’. However the ‘three body problem’ definition neglects the reality that nine countries have nuclear weapons. Any of the nuclear armed states could set off a global nuclear war.   The public needs to relearn the language of nuclear risk and a new generation of leaders will be required to manage these dangers.   

Part 2: How nuclear war could start

To understand how it could all go wrong, look at how it almost did.

By Hans Kristensen, Matt Korda, Eliana Johns and Allie Maloney

Roughly 2000 nuclear weapons that are on alert at any time across the globe. These weapons are ready to launch from submarines, dropped from planes and rocketed to targets. Some are mobile, fixed or in transit; all of them are vulnerable to accidents or affected by human or technical error.    

“The end of humanity could arrive in minutes — that is what makes nuclear war so different from other wars.”

If there is one thing that can be counted on, it’s that nuclear accidents are bound to happen. It’s a matter of when, not if. One of the most dangerous parts of having nuclear arsenals is that accidents involving nuclear weapons could cause an acute global crisis, involving a web of interlocking states, enemies, and adversaries. The delicate balance of crisis can be spurred towards destruction when non-nuclear conflicts spill over into an escalatory spiral towards nuclear use, spelling destruction for all involved. 

Part 3: Only one American can start a nuclear war: The president

The American president has the sole authority to order a nuclear strike, even if every adviser in the room is against it.

By Mackenzie Knight-Boyle

The authority to launch nuclear weapons in the United States rests on the shoulders of only one person, the President. Codified in both law and tradition, the President has the sole authority to launch a nuclear strike that once authorized is unstoppable. The established process to order a nuclear strike, using the ‘black book’, is a well choreographed procedure designed to provide the most streamlined options to the President in a time of crisis.        

“The start of nuclear war, the probable deaths of millions and the choice of which cities to decimate — the black book distills these realities into a sanitized list of options that a former military aide to President Bill Clinton likened to a “Denny’s breakfast menu.”

The Constitution grants to only Congress in Article One the right to declare war. That said, a President has unilateral legal authority to launch nuclear weapons, even if the United States or its allies have not been attacked, runs counter to the way the US system was designed to operate. Such a weighty and world altering decision ought to be made using a system of checks and balances, not by one individual.  

Part 4: What’s making some countries daydream about nukes again?

With or without Iran, the number of nuclear states could double, raising the risk of catastrophe.

By Jon B. Wolfsthal, Hans Kristensen and Matt Korda

The incentives for developing nuclear weapons have changed in a world that has been rising in conflict. Paired simultaneously with reduced confidence among its allies that the United States is a reliable partner, the second largest nuclear armed state, allies and enemies alike are pushed into a new paradigm. Nuclear weapons are hard and expensive to build however with the incentives of security shifting towards development, some countries are willing to front the cost. 

“Deterrence and reassurance depend on both military capability and political credibility. The credibility of a promise to protect is the fragile part of the calculus.” 

A mass proliferation of nuclear weapons would ultimately cause more opportunities for accidents or misuse. This alone is a major reason why limiting the development of nuclear weapons is such a pressing issue. More weapons of mass destruction is more opportunity for things to go wrong, leading to irreversible consequences.  

Part 5: How a nuclear attack on the U.S. might unfold, step by step

The American reaction to an attack is classified, but details made public paint a harrowing picture.

By Mackenzie Knight-Boyle

The process of how the U.S. would react to nuclear attack is classified; however there is a predictable path that it may follow based on public data. This article follows how a response would proceed. The ramifications on U.S. soil and abroad would be devastating.   

“The defense secretary interjects, urging the president to make a decision in the next two minutes or risk losing the ability to retaliate.”

In the situation room, or wherever the President is deciding to make a launch, the space and time pushes the decision towards launch. As U.S. assets are targeted, the potential for ability to respond is shortened. Making the decision window in an accident scenario potentially just as lethal as an intentional launch. Some countries in order to amend this pressure have instituted ‘No First Launch’ policies whereby a country needs to be verifiably attacked with nuclear weapons to respond in kind – such a policy could be used in the U.S. to preempt accidental launch. 

Today is the release of “The Next Nuclear Age” series on the Washington Post.

Q: Your team has a new series on the Washington Post. Can you tell us a bit about what you will be talking about in this series? A sneak peek, if you will.

Hans Kristensen: The world is changing, and it’s changing fast. And we have been working on nuclear security issues for 80 years. And I started working on this in the 1980s, I grew up in the Cold War in Europe. We had this period post-Cold War, of peace and getting together to solve problems. Now it’s changing. The world’s gotten more dangerous. And it’s happening fast. And we want with this series to draw attention to what some of those features are: what are some of the things that are driving this change? That comes an increase in nuclear risks, the risk that nuclear weapons could come into use. The risk that countries begin to build more of them, operate them more offensively, etc, etc. So there are lots of things at stake.

Q: How did this series come to be, and how has this process differed for your team compared to your previous experience in conducting research and reporting on it?

Hans Kristensen: We publish very detailed overviews of nuclear powers [in the Nuclear Notebook], what they do, and their programs. But this particular series in the Washington Post came to be because of the need to communicate to a broader audience. So you can’t get too lost in all the technical details. You have to be able to tell a story, and so we did that and picked a handful of key different aspects of the nuclear problem. And so we hope this comes across as a story about these immense challenges that are facing humanity right now.

Q: Hans, you have been working on the Nuclear Information Project for almost two decades. How has the work evolved since you’ve joined?

Hans Kristensen: FAS was a natural place to go with this project because it was founded by the people who developed the first nuclear weapon and have been in the nuclear business, limiting nuclear risks for all these decades. Later, I came in with the Nuclear Information Project 20 years ago, and for the longest time, it was just little me sitting here working on that, with a few grants. That sort of barely kept me going. As the world began to change, opportunities for funding increased, and we’re able to hire more staff. So now we’re fortunate enough to have six people who are working on this project. And these are people with a very broad range of skills. Everything from deep inside government experience to sort of activism, journalism types of experiences to academic or international organizations experience. It’s a really interesting spread of people that also goes really far in age. We go from early twenties, all the way up to the early sixties.

Q: How have public attitudes and policy frameworks on nuclear weapons shifted since you began working in this space?

Hans Kristensen: Back in the eighties, there was an upswelling of public opposition to nuclear weapons. And people today don’t really believe it, and certainly haven’t experienced it. Most people haven’t experienced it, but we had millions of people, ordinary people, in the streets of Central Park and massive demonstrations across Europe. All the time, people were afraid that our leaders were taking us down a dangerous path. And so they objected and demonstrated. Then the Soviet Union fell apart, and the Cold War ended, and for a period during the nineties, everything sort of got better, and we thought the issue of nuclear would sort of fade more and more into the background, and for sure, there were enormous changes. Since then, I mean, enormous amounts of nuclear weapons were just basically caught up and thrown away. But gradually, this picture started changing, and the political climate soured. We got into skirmishes with each other and and a sort of Cold War attitude returned. But today, most people are sort of still living in the past, meaning the 1990s. “Thinking that there’s this stuff going on doesn’t look good, and whatever. But it doesn’t really affect me personally.” So there’s much less public engagement on this today. It’s not necessarily something that’s going to stay that way. It could be that nuclear risks increase further, and it’s very likely that if they do, there will be much more pressure on politicians from the public

Q: During the freeze movement, there was a lot of public attention on nuclear weapons. Although the total number has decreased, weapon types have evolved. Is there awareness that, despite having fewer nuclear weapons than during the arms race, these weapons remain highly dangerous and are modernizing?

Hans Kristensen: Yes, this is one of the challenges of describing what is happening right now, because people tend to compare it with the Cold War. But the Cold War was particularly nasty. It was the intensity of a global Cold War that was happening all the time. Nukes were everywhere. I mean, they were deployed everywhere. It was extraordinary. That’s no longer the case. That’s the good news. And so the kind of challenge we are now facing is. Yes, there is an increase in nuclear weapons in some countries, but it’s not nearly at the pace of the Cold War. Today, the danger is that we get into these interactions where nuclear weapons are playing a bigger and bigger role. And there are more countries who have nuclear weapons, and more countries in the future will choose to get nuclear weapons. And so the pathways to the potential use of nuclear weapons have increased more than the number of nuclear weapons.

Q: Who do you most hope engages with this series, and what do you hope they take away?

Hans Kristensen: We want them to come out of it with a raised nuclear IQ, that gives them a broader picture, sort of in a concentrated framework, to be able to relate to this nuclear challenge we have today. And we certainly hope that people will be motivated to contact their congresspeople, write articles, and engage with other people. The whole shebang about how to influence public policy. But it’s also a debate for people who are in government, because many people who are in government today don’t have any Cold War experience. And so they were young people who came in. They don’t have that personal background. They need to be educated about this as well. So it’s really a series of articles that has to span widely and reach a very broad range of people from different backgrounds.

Q: What makes this series especially timely, given the growing disregard for information?

Hans Kristensen: It’s the importance of putting out information about these issues, to raise the nuclear IQ with people. Without information, without factual information, you can’t act. You can’t relate to the world you live in. And so it’s super important for us to be able to monitor what’s happening around the world, analyze the material, and translate it into something that different audiences can understand. So we’re fortunate enough that our material here on the project is being used around the world all the time. I mean, our factual pieces are used as the basis for newspaper articles, television shows, books, magazines, conversations, and briefings around the world. So it’s an extraordinarily privileged situation to be in, to be able to contribute and empower the public debate with facts.

President Trump is moving quickly to push U.S. allies to invest even more in their own defense. NATO allies have already committed to spend 3% of their GDP on defense, yet the U.S. is now calling for them to spend at least 5%. It is likely that U.S. allies in East Asia will soon face similar calls to do more. Greater investments in conventional capabilities make a lot of sense. However, there are some U.S. policy experts, officials and academics calling for more U.S. allies to go nuclear to reduce U.S. defense requirements. These calls are dangerously misguided and ignore the threat any proliferation – including by U.S. allies – poses to American security interests. They must be rejected wholesale by the Trump Administration.  

One of the most enduring successes of U.S. national security policy has been its effort to limit the number of states with nuclear weapons. Predictions that dozens of countries might possess nuclear weapons did not materialize because of concerted U.S. actions. The risks include the reality that U.S. allies can and often do experience internal instability or even regime collapse, that any state with nuclear weapons creates a risk that those materials or knowhow can be stolen or diverted, that any state with nuclear weapon in a crisis might actually use those weapons, and lastly the reality that states with their nuclear weapons are less susceptible open to U.S. influence. There may be reasons why a state may want to go nuclear from their own perspective but there are few if any lasting benefits to American security that comes from proliferation to friends and allies.

Nine countries currently have nuclear weapons, but perhaps 40 additional states are technically advanced enough to build nuclear weapons if they chose to do so. Many of these states are U.S. allies or partners, including in Europe as well as Japan, South Korea, and even the island of Taiwan. That these states never went nuclear (although some tried) is due to a combination of factors, including the credibility of U.S. defense commitments to their security, the pressure America brought to bear when these states indicated a potential interest in building independent nuclear arsenals, and the recognition that if the world was serious about getting rid of all nuclear weapons then their spread was a step in the wrong direction.

The re-election of Donald Trump has understandably spooked many U.S. allies, renewing doubts that America will come to their aid. The growth of China’s military and economic power relative to the United States is adding to these concerns. More allies are asking now, just as they did during the Cold War if America would really risk Boston to protect Berlin, or Seattle to protect Seoul. As this question festers and as America’s relative power over China and other states ebbs, the lure to encourage U.S. friends to develop nuclear weapons of their own to deter or defeat an attack will grow. After all, the theory goes, why should the United States worry if its friends go nuclear?

In the real world, however, the spread of nuclear weapons anywhere complicates and undermines U.S. security. One reason is states are not always stable. In the 1970s, the U.S. supported its Treaty partner Iran acquiring nuclear reactors and advanced technology but in 1979, that regime was overthrown by the Islamic Revolution. Pakistan went nuclear when the U.S. needed its help fighting the Soviets in Afghanistan, and has faced wave after wave of instability and crisis. And South Korea is a more recent challenge. For the last few decades, South Korea was considered a stable and vibrant democracy – even hosting a Summit for Democracy last year. Under President Yoon, South Korea has voiced increasing interest in an independent nuclear arsenal. And just last year, a former Trump official, Elbridge Colby, expected to serve in a senior policy role at the Pentagon publicly encouraged South Korea to build their own nuclear weapons to deter North Korea and enable the U.S. to focus more on China. The situation in South Korea, with an impeached President and no clear sense of who controls the country’s military, would be a lot more dangerous if Seoul had nuclear weapons. 

This is not just an issue for newer nuclear weapons states. Prior to the Soviet Union’s collapse in 1991, a coup created confusion for days over exactly who had the ability to control Soviet nuclear weapons.  Following the USSR’s demise, nuclear weapons and materials remained at risk of theft and diversion for years and required massive U.S. efforts and investments to prevent their loss. And even the United States is not immune from these risks. The 2021 insurrection raised nuclear risk to the point that the Speaker of the House had to publicly ask the Chairman of the Joint Chiefs about the risk that President Trump might use nuclear weapons in a gambit to remain in power, and Chairman Milley took extraordinary steps to insert himself into the nuclear chain of command to preempt that risk. Any nuclear arsenal anywhere is a potential danger if political circumstances change.

And states with nuclear weapons create a nuclear risk if nuclear technology, materials and knowhow are stolen or diverted. Five of today’s nuclear weapon states – America, Russia, China, France, and Pakistan – have either knowingly or unwittingly helped other states go nuclear.  Even if theft or transfer were not an issue, when new states have gone nuclear in the past, others have followed. America’s nuclear success led the Soviet Union to build them as well. This in turn led the UK and France to follow suit. These four nuclear weapon programs fueled China’s desire to join the club. Beijing having the bomb drove India to do the same, which then led Pakistan to follow suit.  

And any nuclear state might decide one day to use those weapons. Every nuclear leader must get every nuclear decision right, every time or boom. The history of U.S. and Soviet nuclear deterrence is marked as much by nuclear misunderstandings and potential accidents as by stable deterrence. India and Pakistan have the same problem. It is reasonable to assume new nuclear states with nuclear weapons would encounter many of the same risks.

And finally, from a very direct Americentric point of view, each state that acquires their own nuclear weapons lessens the ability of the United States to influence, control or dictate security outcomes in that state and region. While not the message U.S. diplomats use openly when trying to work diplomatically to stop proliferation, the issue of influence is as relevant to U.S. allies as adversaries. To the extent that the U.S. security is enhanced by being able to heavily influence how states around the world act, then enabling the spread of nuclear weapons undermines that ability.

It is and will continue to be tempting for the next Administration to find rapid and easy solutions to long-standing security challenges. Empowering U.S. allies to do more so Washington can do and spend less, or focus more effectively on fewer challenges is an understandable policy outcome. But enabling, or looking the other way at the spread of nuclear weapons is not in America’s interests anymore today than it was in the 20th century.