An October 2025 social media post by the U.S. president instructed the Department of Defense to begin testing nuclear weapons. But is it really necessary?

BY MARK GOODMAN AND MONTE MALLIN

On October 30, 2025, President Donald Trump posted on Truth Social that the United States would resume nuclear testing. Though it came as a surprise to many, it was one of the recommendations in the Heritage Foundation’s Project 2025 policy initiative, which in many ways has served as a blueprint for the Trump administration.

The president’s announcement raised many questions about its intent, not least because it seemed to misstate several important facts. For example, the post asserted that the United States has more nuclear weapons than any other country, when in fact Russia is known to have a greater number overall, if nondeployed warheads are included. While China is increasing its stockpile by roughly a hundred per year, it is not, as Trump asserted, on the verge of matching the United States.

Similarly, the announcement instructed the Department of War [sic] to prepare for a test, but the maintenance—and potential testing—of nuclear weapons is the responsibility of the Department of Energy’s National Nuclear Security Administration (NNSA).

Of greater concern, however, was the substance of the president’s social media message: The United States would resume nuclear testing. This was largely interpreted as a reference to nuclear explosive testing. The United States has not conducted a nuclear explosive test since 1992, when it declared a formal moratorium; since 1998, only North Korea has done so, in 2017, almost a decade ago.

The Comprehensive Nuclear-Test-Ban Treaty (CTBT), which bans all nuclear explosive testing, was opened for signature in 1996, but has not yet entered into force because key states, including the United States, have not ratified it. Yet it has played an important role in creating a norm against such testing and in building an international monitoring system.

Some have suggested that the president’s announcement should be read as a call for testing of nuclear delivery systems, the missiles and aircraft that carry nuclear bombs and warheads. The announcement referred to other countries’ testing programs, and indeed Russia had tested new types of nuclear delivery systems in the preceding weeks.

U.S. Secretary of Energy Chris Wright sought to allay concerns with this explanation: “I think the tests we’re talking about right now are systems tests. These are not nuclear explosions. These are what we call noncritical explosions.” Secretary Wright went on to note that these tests would involve “the other parts of a nuclear weapon” rather than the nuclear explosive itself.

Of greater concern, however, was the substance of the president’s social media message: The United States would resume nuclear testing.

Despite these reassurances, exactly what the administration has in mind remains unclear. The benefits of resumed nuclear explosive testing are marginal, but the costs are clear: it would add significant instability to today’s already precarious security environment. This is not 1996, when many countries were cooperating to reduce nuclear threats. It’s a very different, and more competitive, world.

What’s at Stake?

Of all the countries that possess nuclear weapons, the United States has the least to gain and the most to lose by a resumption of nuclear explosive testing. Russia has conducted fewer, and China far fewer, nuclear tests than the United States, and both countries have far more to gain from renewed nuclear explosive testing.

For decades, the United States has sustained an extensive science-based Stockpile Stewardship Program that ensures the reliability, safety, security, and effectiveness of its nuclear stockpile through advanced, highly sophisticated science and engineering programs. It encompasses multiple efforts across all NNSA laboratories, plants, and sites, including the NNSA nuclear weapons laboratories (Sandia, Los Alamos, and Lawrence Livermore).

This program ensures that the United States maintains a safe and effective nuclear deterrent without nuclear explosive testing. Every year, the directors of the nuclear weapons labs are required by Congress to certify that the program is meeting its objectives. This has occurred without fail since 1996. The certification was last completed on September 22, 2025, just a few weeks before the president’s post. If something changed radically in the few weeks between the certification and the announcement, it would be a pretty big surprise (especially to the lab directors).

“Because of other countries’ testing programs,” the president’s post read, the United States would resume testing of our nuclear weapons “on an equal basis.” The reference to other countries seems to point to a 2021 report in which the State Department concluded that Russia, and possibly China, had conducted very low-yield nuclear tests that (unlike the subcritical tests Secretary Wright referred to) are inconsistent with the zero-yield standard set by the CTBT. A State Department official stated in February 2026 that China had conducted such low-yield tests.

According to former NNSA Administrator (and former Sandia National Laboratories Director) Jill Hruby, such low-yield tests would provide additional information but are not needed for stockpile stewardship.

Russian President Vladimir Putin responded to the Trump post in early November, stating that Russia would take “reciprocal measures,” and has reportedly asked his security council to draft options to resume such testing. Moscow had withdrawn its ratification of the CTBT in 2023, saying it sought the same status as the United States, but stated at the time that it would not resume testing unless the United States did so first.

The Wrong Signal

If the United States breaks its own moratorium, it sends a clear signal not just to Russia and China but also to other countries that testing could be a tenable option. India and Pakistan last conducted explosive testing in 1998 and have maintained test moratoria since then, but a resumption of U.S. testing would reduce constraints they may have with respect to a resumption of testing. This is an already volatile region, and the prospect of new nuclear arms racing, not just in South Asia but potentially in China as well, is not something the United States should encourage.

Though North Korea has not tested since 2017, the country remains ready to test. It does not have a formal, declared moratorium but has exercised some restraint in the past, and the United States has nothing to gain by opening the door to a resumed testing program.

The United States has little, if anything, to gain from resuming nuclear testing and much to lose if it does so.

More broadly, nuclear explosive testing would send exactly the wrong signal to the international community about the U.S. commitment to widely shared nuclear nonproliferation and disarmament objectives. Halting nuclear testing has long been a critical goal of efforts to prevent nuclear war and nuclear proliferation. The first multilateral disarmament treaty was the 1963 Limited Test Ban Treaty, which prohibited nuclear testing everywhere except underground and, in its preamble, expressed the goal of ending all nuclear tests.

The NPT Under Pressure

Nuclear explosive testing is a key step for any country seeking a nuclear weapon. Indeed, China’s first nuclear test in 1964 was one of the factors that galvanized the international community to negotiate the Non-Proliferation Treaty (NPT), which entered into force in 1970, initially for 25 years.

The NPT recognizes five countries—the United States, Russia, France, the United Kingdom, and China—as nuclear-weapon states; all others joined the treaty as non-nuclear-weapon states, committing not to pursue a nuclear weapon. NPT parties committed to pursue good-faith negotiations to end the arms race and toward nuclear disarmament. The NPT preamble calls for “the discontinuance of all test explosions of nuclear weapons for all time,” which all parties recognized to be an essential step for both nonproliferation and arms control.

And when the NPT was extended indefinitely in 1995, the parties adopted the objective of completing CTBT negotiations in 1996. This commitment from the nuclear-weapon states to prioritize completion of the CTBT helped to secure the indefinite extension of the NPT.

But the NPT is already under pressure. Many non-nuclear states are frustrated with the lack of progress on nuclear disarmament and with the modernization and expansion of some countries’ nuclear arsenals. Iran has threatened to withdraw from the NPT over the reimposition of United Nations sanctions. Saudi Arabia has said it intends to acquire nuclear weapons if Iran does, and others in the Middle East could follow suit. Politicians and advocates in South Korea, Germany, and Poland have questioned the reliability of the U.S. nuclear umbrella and advocated for or entertained the idea of acquiring nuclear weapons of their own.

A Prudent Approach

In short, the United States has little, if anything, to gain from resuming nuclear testing and much to lose if it does so. It would represent an abdication of U.S. leadership in nuclear nonproliferation and undercut long-standing U.S. commitments to nuclear restraint. It would open the door for others to follow suit in ways that increase risks of nuclear competition and confrontation around the globe. Rather than adding to the pressures on the nuclear nonproliferation regime, the United States should be reaffirming and reinforcing its commitment to nuclear nonproliferation objectives.

Secretary Wright’s formula represents a prudent approach that would enable the United States to maintain its nuclear stockpile to the highest technical standards, thereby maintaining a safe and effective nuclear deterrent. It is a sensible approach to clarifying the president’s intentions and would not undercut our long-standing leadership in advancing global nuclear nonproliferation objectives.

Mark Goodman is a nonresident fellow at the James Martin Center for Nonproliferation Studies. He retired in 1995 after serving for 30 years as a U.S. government policy expert and a leading practitioner of multilateral nuclear nonproliferation diplomacy at the Department of State, the Department of Energy, and the Arms Control and Disarmament Agency, most recently in 2025 as senior scientist in the State Department’s Office of Multilateral Nuclear and Security Affairs. Goodman has a PhD in physics from Princeton University and is a fellow of the American Physical Society.

 

Maurice “Monte” Mallin is a senior fellow at Sandia National Laboratories. In April 2025, he retired from 30 years of federal service as the director of policy for the National Nuclear Security Administration. Mallin also served at the National Defense University as the chair for nuclear security programs, as well as at the State Department and the Arms Control and Disarmament Agency. He was a key member of the team that negotiated the Comprehensive Nuclear-Test-Ban Treaty, which opened for signature in 1996.

Read More...

• “Trump, Acheson, and the H-Bomb” by Barton J. Bernstein, The Foreign Service Journal, June 1983
• “The Importance of Verification” by Paula A. DeSutter, The Foreign Service Journal, December 2009
• “Common Misconceptions About the NPT: A Practitioner’s Guide” by Mark Goodman, Bulletin of the Atomic Scientists, August 2025
• The Negotiator Files: A Conversation with Monte Mallin, CSIS Project on Nuclear Issues, November 2025