State Department Claims Spark Fresh Tensions
A new accusation from the US State Department has reopened a long running debate in Washington over nuclear weapons testing. Officials claim that China carried out a small yield nuclear test in 2020, despite its public pledge to uphold a testing moratorium.
Thomas DiNanno, a senior State Department official, said the US government believes China conducted an explosive test at its Lop Nur site on June 22, 2020. He also claimed Beijing may be preparing additional tests in the hundreds of tons range. If true, that would mark a serious step in China’s nuclear modernization.
In response, China denied the allegation. Its foreign ministry accused Washington of politicizing the issue and insisted that Beijing still follows a voluntary ban on nuclear tests.
Even so, the claim has intensified concerns about verification and deterrence. It has also raised a key question. Can the United States continue relying on computer simulations instead of live detonations?
Why Small Nuclear Tests Are Difficult to Detect
Modern nuclear tests differ sharply from the massive atmospheric blasts of the Cold War. Today, countries conduct tests deep underground. As a result, detection becomes much harder.
Experts warn that techniques such as decoupling can weaken seismic signals. In simple terms, a device detonated inside a large underground cavity produces a smaller seismic signature. That makes it harder to separate from natural earthquakes.
This issue has long complicated debates around the Comprehensive Nuclear Test Ban Treaty. Although China signed the treaty in 1996, it never ratified it. The treaty itself has not entered into force.
Critics argue that even small underground detonations can provide useful weapons data. Therefore, limited tests may still advance a country’s arsenal while avoiding clear detection.
Are Simulations Still Enough?
For more than three decades, the United States has relied on its Stockpile Stewardship Program. This program uses advanced modeling and simulations to maintain the reliability of nuclear weapons without explosive testing.
However, some analysts now question whether that approach remains sufficient. They argue that if rivals conduct live tests, simulations alone may not keep pace.
Others disagree. Henry Sokolski, head of the Nonproliferation Policy Education Center, says restarting live testing would be costly and complex. He notes that the United States carried out more than 1,000 tests during the Cold War. That massive database now supports current modeling efforts.
Restarting full scale testing, he argues, would require years of preparation and major funding. In his view, the debate centers on technical needs and costs, not ideology.
Concerns Over Deterrence and Allies
The debate extends beyond laboratories. It also touches on extended deterrence, the US promise to defend allies under its nuclear umbrella.
Countries such as Japan and South Korea rely on those guarantees. If doubts grow about US capability or resolve, regional stability could suffer. As a result, policymakers must weigh both technical data and geopolitical consequences.
For now, US lab directors continue to certify that the arsenal remains safe and reliable without explosive testing. Still, some experts warn that sustained testing by competitors could eventually shift that assessment.
Former President Donald Trump has suggested the United States should test on an equal basis if rivals do. However, no formal policy change has been announced. Any return to explosive nuclear testing would mark a major shift in US strategy.
