Debate Intensifies Over U.S. Nuclear Testing Policy After China’s Alleged Test

The U.S. State Department has sparked renewed discussions in Washington regarding the potential continuation of America’s long-standing nuclear testing moratorium. This follows claims that China conducted a nuclear test capable of yielding significant energy back in 2020.

There are concerns among U.S. officials that China may be gearing up for tests involving hundreds of tons of explosives. This would reflect the ongoing modernization of China’s nuclear capabilities and complicate efforts to engage in arms control talks.

U.S. Officials Present Evidence

Thomas DiNanno, who serves as Under Secretary of State for Arms Control and International Security, recently mentioned evidence indicating that China has indeed executed a nuclear explosion test at the Lop Nur facility.

“I can confirm that the U.S. government is aware of China’s nuclear explosion tests, including preparations for those with yields in the hundreds of tons,” DiNanno noted during address at the United Nations Conference on Disarmament. He added that a test producing such a yield occurred on June 22, 2020.

DiNanno further alleged that China employed techniques designed to “decouple” explosive devices, making the seismic signals less detectable, thus hiding their activities from global scrutiny.

In contrast, China’s Foreign Ministry has flatly denied these accusations, suggesting the U.S. is politicizing nuclear issues and reaffirming that it maintains a voluntary testing halt.

Implications for U.S. Policy

The recent claims raise questions about whether the U.S. stockpile management strategy, which relies on verification measures and computer simulations, can still be effective amid increasing nuclear competition.

Challenges in Detecting Small-Scale Nuclear Tests

Detecting smaller-scale underground tests has historically posed a dilemma in arms control. Unlike the large atmospheric tests of yesteryear, today’s nuclear tests are often deep underground. Techniques like “decoupling” can significantly lessen the seismic signals, making it nearly impossible to differentiate these from natural activity.

This topic has been a point of contention in discussions about the Comprehensive Nuclear-Test Ban Treaty, which China signed but has yet to ratify. Although detecting smaller tests is tough, they can provide critical information about weapon capabilities.

Are Simulations Sufficient?

Even though China signed the Comprehensive Nuclear-Test Ban Treaty in 1996, it hasn’t ratified it, and continues to maintain a voluntary testing suspension that contradicts these actions.

The longstanding principle of “trust but verify” now faces strains as China progresses in expanding its nuclear stockpile and undermines vital arms control mechanisms.

Voices Within the Community

DeBoer argues the arms control community has lost credibility, suggesting that Western restraint might not yield favorable responses from Beijing. Meanwhile, the U.S. has leaned heavily on stockpile management programs to assure its nuclear reliability without the need for detonation tests. However, this approach may not suffice should other nations pursue real detonations.

Counterpoints exist, with experts like Henry Sokolsky, director of the Center for Nonproliferation Policy and Education, expressing skepticism about resuming explosive testing. He emphasized the complexities and costs involved in achieving meaningful outcomes from nuclear testing.

Sokolsky noted, “It’s not merely about whether one supports or opposes nuclear arms; what’s critical is understanding what’s technically necessary and economically feasible.” He highlighted that the extensive testing conducted during the Cold War required many trials to gather substantial data.

Internal Disagreement on Testing Strategies

This debate isn’t just happening externally but is also alive within the U.S. weapons community. Some, particularly at facilities like Livermore, advocate for using simulations, while others see value in maintaining the option for empirical testing.

Impact on U.S. Alliances

The ramifications stretch beyond the U.S. and China, with Sokolsky warning that doubts surrounding America’s commitment may compromise the reliability of U.S. nuclear assurances to allies.

Countries like Japan and South Korea rely heavily on U.S. nuclear guarantees instead of developing their own arsenals, so any potential shift in perception could disrupt regional stability and longstanding efforts to prevent proliferation.

A Crossroads for Policy

Currently, U.S. laboratory directors aim to ensure that the nuclear arsenal remains safe and reliable without resorting to detonation testing. However, Heather Williams from the Center for Strategic and International Studies cautions that continued testing by rivals could alter this perspective.

The core issue for U.S. policymakers transcends the question of whether to conduct tests; it also hinges on understanding the conditions under which testing could effectively enhance deterrence rather than escalate competition.

President Trump’s past suggestions about resuming tests to match competitors signal a potential shift in U.S. nuclear policy, although no formal changes have been articulated from the administration. In October 2025, Trump floated the idea of U.S. nuclear tests being “equal” to those of other nations—yet it remains unclear if he meant full detonations or alternative evaluation methods. Resuming testing would mark a significant departure from the current U.S. stance on nuclear arms.

As discussions evolve, one thing remains clear: the landscape of nuclear strategy continues to shift amidst a blend of national security challenges and diplomatic complexities.