Nuclear weapons have been in the headlines—and on our screens–lately. Indeed, nuclear tensions are on the rise. According to SIPRI, nearly all nuclear-armed states are upgrading and enlarging their arsenals, some for the first time since the end of the Cold War.
Kathryn Bigelow’s new film, A House of Dynamite, asked the question: what might happen if an unexplained nuclear crisis or conflict starts that directly threatens the United States? Despite its inconclusive ending, it explored how easily we could spiral into uncontrolled escalation if we do not find ways to step back from the nuclear brink.
Late last month, U.S. President Donald Trump instructed the Department of War to “start testing our nuclear weapons on an equal basis” with Russia and China–which, depending on how it is implemented, could potentially mark the first U.S. explosive nuclear test in three decades. The decision introduced a dangerous level of ambiguity into U.S. nuclear posture. And in response, Russian President Vladimir Putin instructed Kremlin officials to “submit coordinated proposals on the possible first steps” for also resuming nuclear weapons tests if the United States starts their own.
What lessons can we take away from A House of Dynamite? What does the escalation of nuclear testing mean for global security and stability? And what is IST doing to advance nuclear risk reduction? To answer these questions and more, I sat down with IST’s Nuclear Policy team: Director of Nuclear Policy Sylvia Mishra, Senior Policy Advisor Sahil V. Shah, Senior Associate for Nuclear Policy Brandon Cortino, and Associate for Nuclear Policy Catherine Murphy.
Q&A with IST Experts on Rising Nuclear Tensions—and What We’re Doing About It
What are your thoughts on A House of Dynamite? What lessons should we be taking away from the film?
Catherine Murphy: “A House of Dynamite could not be more timely. It’s a sobering reminder that nuclear risk should very much still be a part of the public’s conscience. As the United States, Russia, and China expand their nuclear arsenals, and the New START treaty, which is the last remaining arms control treaty between the United States and Russia, is set to expire in less than three months, the risks of nuclear use are at their highest since the Cold War. For me, the most important takeaway is that, even though the decision to use nuclear weapons lies with a handful of world leaders, I think the public still has influence in shaping nuclear policy. The film serves as an important reminder for us to continue to stay engaged on nuclear policy issues and urge leaders of nuclear-armed states to take measures to reduce the risk of nuclear war. Movies like Bigelow’s should spark a new sense of urgency and a call to action that echoes the sentiments of the Cold War, urging world leaders that ‘nuclear war cannot be won and must never be fought.’”
Exactly how realistic is the film? What tracks with current practices, and what doesn’t?
“While the scenario is fictional, the movie attempts to illustrate a close picture of how the United States assesses incoming threats and determines whether and how it launches nuclear weapons. It raises important questions about the United States’ preparedness for a nuclear crisis. For example, the film illustrates the President’s panic over the fact that he received only one briefing at the outset of his term, and it was the first time he saw the “Nuclear Handbook” – the binder of options for nuclear targeting and launch options. Previous U.S. Presidents have had varying degrees of experience on the topic of nuclear weapons, but the film points out that U.S. Presidents may need more preparation and exercises to deal with nuclear crises. In addition, A House of Dynamite portrays the challenge of communicating with the United States’ adversaries. In the film, the White House is unable to connect the President with his counterparts in Russia, China, and North Korea as they attempt to determine who launched the missile. For me, this highlighted one of the key challenges that I focus on in my work at IST: existing multilateral communication channels are patchy, and not all leaders of nuclear-armed states can be reached safely and securely in the face of mounting tensions and crises.
For all of its plausible scenarios, A House of Dynamite still strayed from reality in a few key places. Numerous nuclear policy experts and former government officials have pointed outinaccuracies in the operational processes depicted in the film, such as the characters’ automatic assumption that the warhead on the incoming missile is nuclear, not conventional. Also, the incoming strike comes as a complete surprise, with no prior conflict to portend the escalation. While this might have been a concern for much of the Cold War, today, the leading narrative on the most likely pathway to nuclear use consists of prior conventional-level conflict. Another scene in the film that does not align with current practice is when the President considers the range of retaliation options from the binder without actually knowing which actor launched the missile to begin with. As other experts have pointed out, it is highly unlikely that the United States would haphazardly assess nuclear target options if it did not know who fired the warhead to begin with.”
Why exactly is Trump’s declaration to resume arms testing so dangerous? Did you see any surprises from Putin’s response?
Sahil V. Shah: “Trump’s declaration is dangerous because ambiguity about nuclear intent can be just as destabilizing as an actual test. In my Foreign Policy piece, I explained that a loose phrase like “resume nuclear testing” can refer to very different things—ranging from routine missile-system tests to the far more consequential step of authorizing explosive nuclear detonations for the first time in decades. Foreign governments don’t wait for clarifications; they react to signals and often assume worse-case intent. And when a U.S. president blurs those lines, it shifts assumptions in Moscow, Beijing, and elsewhere in ways that can accelerate arms-race dynamics overnight.
Putin’s response didn’t surprise me, but it was revealing. By publicly directing his government to “collect additional information” on the U.S. position and “prepare options” while insisting Russia is not conducting low-yield tests, his message was consistent with previous comments: deny wrongdoing, but threaten symmetrical action if the United States shifts course. That’s exactly the tit-for-tat spiral both Washington and Moscow should want to avoid, especially because neither has much to technically gain from reopening the door to explosive nuclear testing.”
What will you be looking out for going forward?
“Going forward, I’ll be watching three things.
First, whether the administration tries to retrofit a policy justification around Trump’s remark—because it’s so fuzzy, Trump could point to a routine missile launch dressed up with political fanfare and claim he has “tested our nuclear weapons,” or, on the opposite end of the spectrum, he could push toward openly contravening the Comprehensive Nuclear-Test-Ban Treaty zero-yield norm with explosive nuclear testing.
Second, whether Russia or China use this ambiguity as political cover to harden their own positions and drift further from the Comprehensive Nuclear-Test-Ban Treaty’s spirit and letter. Given the state of great-power relations, it isn’t just the big bangs that matter, but the gray-zone activities that blur the line and drive escalation.
And third, the domestic incentives beneath all this: who in Washington is trying to make their budget or agency relevant, who benefits from the manufactured crisis, and what might this spectacle be distracting from?”
What is the New START Treaty?
Brandon Cortino: “The New START Treaty is the most recent major bilateral nuclear arms control treaty between the United States and Russia. It came into force in February 2011, and superseded the 2002 Moscow Treaty, an agreement that I researched extensively through my CSIS Future Arms Control Experts fellowship.
New START limits both the United States and Russia to deploying a maximum of 1,550 warheads, backed up by extensive verification measures to ensure both sides stick to the arrangement. It is in some ways a relic of the past: it was signed when Dmitry Medvedev was Russia’s President, at a time when Russian leadership was more open to cooperation with the West. The treaty was originally written to last for 10 years, with a mechanism to allow a maximum of a 5-year extension. This brings us to February 2026, when the treaty is set to expire. Attempts to negotiate a follow-on treaty have been ongoing for several years, to no avail. When New START expires, we could be left with no major bilateral treaty between the United States and Russia to limit strategic arsenals.”
Let’s put this in context. Why is this treaty so important?
“New START matters because it maintains a framework for cooperation and trust building between the United States and Russia at the most unstable moment in great-power relations since the end of the Cold War. Recently, Russian President Vladimir Putin proposed extending New START informally, signaling interest in maintaining some form of strategic cooperation. So far, the Trump administration has expressed a willingness to informally extend the treaty. However, Putin offered this treaty extension without any mention of verification measures, which raises questions about his long-term intentions and how 2027 force planning will look after the informal extension expires.
I believe extending for a year does no meaningful harm to interests in the nuclear space and is a symbolic overture for strategic cooperation. The short extension period of one year gives both the United States and Russia flexibility to adapt force planning using stockpiled warheads over the period of a few months, should the need arise at the conclusion of any optional and informal extension. If the U.S. government decides that it is in the American interest to deploy more warheads to simultaneously hold both China and Russia at suitable risk, the United States can in theory arm more missiles in 2027. However, this is unlikely to meaningfully alter the strategic balance, and is likely already being considered for force planning ever since China’s push to expand its nuclear arsenal began during the first Trump administration. It is worth noting that the 1,550 warhead limitation was agreed upon by both the United States and Russia as an appropriate number to adequately devastate the opposing side’s military infrastructure in the event of a nuclear exchange. Even with China’s efforts to develop their nuclear capabilities, I don’t see anything that leads me to believe there is a need for a higher number of deployed warheads at this time.”
With nuclear tensions on the rise, what is IST doing to reduce nuclear risks and improve crisis communications? Can you share some of the latest work out of the Nuclear Policy team, and what’s to come?
Sylvia Mishra: “Nuclear weapons have come back into sharper focus, and as nuclear-armed states continue to modernize and expand their arsenals, investing in nuclear risk reduction efforts is of paramount importance. At IST, we take our mandate to reduce nuclear dangers seriously and are advancing these efforts on multiple fronts.
Our Nuclear Policy team is leading the CATALINK initiative, which addresses the critical need for multilateral crisis communication. Earlier this year, the team presented our work on the sidelines of the United Nations General Assembly. We are simultaneously investigating how emerging technologies may undermine nuclear crisis communication channels. To raise the profile and visibility of this initiative, we have partnered with a media production company to launch a short CATALINK video explainer. Looking ahead to 2026, the team is designing a tabletop exercise with leading stakeholders and policymakers to illuminate the challenges of effective nuclear crisis communications, particularly during crises and in their lead-up.
In addition, IST has launched a multi-year effort at the intersection of artificial intelligence and nuclear command, control, and communication systems (NC3). The team has established an executive committee—a highly selective group of experts, high-ranking officials, and former U.S. Strategic Command leaders—to help shape the research agenda. Four distinct working groups (AI Competitive Dynamics; AI Global Perspectives; AI Technical Trajectory; and AI Norms and Governance), consisting of senior experts from diverse fields across the nuclear policy landscape, will develop actionable policy recommendations. By the project’s conclusion, IST aims to engage policymakers in the U.S. and internationally to advocate for the responsible, safe, and secure integration of AI in NC3 systems.”
