National Interest

by Andrea Stricker

    Clarity is key on most issues relating to nuclear weapons and testing them is no exception.

    America’s adversaries are carrying out low-level nuclear tests and gaining an advantage over the United States in modernizing their arsenals, according to President Donald Trump and CIA Director John Ratcliffe. The United States considers these tests by Russia and China to be a violation of the voluntary “zero-yield” moratorium that nuclear-weapons states have been obliged to observe since the 1990s.

    At least partly in response, the president announced new US nuclear weapons tests on October 29. While Trump’s announcement could mark a dramatic change in posture for the United States, news of Moscow and Beijing’s malfeasance is not new. US government reports and assessments have indicated since at least 2019 and 2020, respectively, that Russia and China are likely conducting low-level nuclear weapons tests, consistent with the CIA’s recent findings.

    Energy Secretary Christopher Wright subsequently clarified that US tests will not involve similar low-level testing, which would entail brief or sustained nuclear chain reactions and explosions. Still, Russia appears to be taking Trump’s announcement seriously. On November 5, Russian President Vladimir Putin ordered officials to prepare options for testing Moscow’s nuclear weapons.

    Since the matter appears unsettled—and is causing a stir among US adversaries and allies alike—the United States must clarify whether it is shifting toward abandoning its more than three-decade commitment to abstain from low-level nuclear testing.

    The confusion stems from an October 29 post by Trump on Truth Social, “Because of other countries[’] testing programs, I have instructed the Department of War to start testing our Nuclear Weapons on an equal basis,” specifically citing Russia and China’s nuclear activities. In a 60 Minutes interview, he clarified that while he would prefer “denuclearization”—likely referring to nuclear arms reductions—he does not want the United States to be the only nation not conducting tests.

    Trump stated, “Russia’s testing and China’s testing, but they don’t talk about it.” He added, “They test way [underground] where people don’t know exactly what’s happening with the test,” also identifying Pakistan and North Korea as countries conducting such tests. He emphasized that the United States must also conduct nuclear weapons tests to ensure their functionality.

    Since no country except North Korea has conducted large-scale nuclear tests since the 1990s, Trump was likely referring to covert, underground, very low-yield tests that trigger a brief or sustained nuclear chain reaction and small explosion, as seemingly confirmed by Ratcliffe. Such tests are likely undetectable by the global network of seismic and other sensors designed to monitor nuclear blasts and enforce the 1996 Comprehensive Test Ban Treaty (CTBT).

    Of the five recognized nuclear-weapon states, the United States and China signed but did not ratify the CTBT, while Russia ratified it but withdrew its ratification in 2023. The United Kingdom and France have fully ratified the treaty; however, due to insufficient ratifications, including those from de facto nuclear-armed states and other nations, the CTBT is not yet in force.

    However, since 1998, states with nuclear weapons have generally observed a global moratorium on large-scale nuclear testing, except for North Korea, which last tested in 2017. In addition, the recognized nuclear weapon states agreed during pre-1996 CTBT negotiations to the zero-yield testing standard. Under the 1990 Protocol to the Threshold Test Ban Treaty, Russia and the United States must also notify one another and permit verification of nuclear explosive testing activities.

    “The testing that we’ll be doing is on new systems,” said Wright on November 2, referring to tests of modern US nuclear designs. “I think the tests we’re talking about right now are system tests.” He added, “These are not nuclear explosions. These are what we call non-critical explosions, so you’re testing all the other parts of a nuclear weapon to make sure they deliver.”

    Such tests would ostensibly not surpass the current US zero-yield testing threshold. Instead, they would be intended to ensure the functionality and safety of the US nuclear stockpile with explosives without sustaining a chain reaction and creating a nuclear explosion, unlike what Washington suspects Beijing and Moscow are doing. The United States relies on supercomputers, simulations and other experimental methods for such zero-yield testing.

    There has long been a debate within the US national security establishment about the merits of resuming low-level nuclear testing, as adversaries do, versus preserving the zero-yield moratorium to prevent global testing escalation.

    Proponents of low-level testing seek to match adversaries’ warhead data to bolster an aging US nuclear arsenal and strengthen deterrence. The National Academy of Sciences (NAS), for example, acknowledged in a 2002 report that while nuclear testing is not essential, testing would certify “the performance of new designs at the level of confidence associated with currently stockpiled weapons.” However, the US National Nuclear Security Administration has asserted confidence that US technologies have kept pace to ensure the reliability of the nuclear arsenal—including newer designs—without testing beyond zero yield.

    Moreover, China, with fewer than 50 tests prior to the 1990s moratorium—compared to more than 700 by Russia and 1,000 by the United States—and an ambitious nuclear modernization plan, stands to benefit most from open low-level testing. US testing would also cost hundreds of millions to billions amid lengthy and expensive delays in US nuclear modernization.

    As the matter of nuclear testing is already heightening tensions, the Energy Department should continue to clarify the technical parameters of new US tests and whether the administration intends to abandon the zero-yield policy.

    Washington must justify the technical benefits of resuming low-level testing against risks to the global testing moratorium, including the potential for triggering full-scale testing worldwide and further proliferation of nuclear weapons.