Author name: Peter Zambelli

Resuming full testing of nuclear weapons, as President Donald Trump called for last week, would be unnecessary and costly, risk undermining nonproliferation efforts, and empower adversaries to use their own tests as intimidation, experts told Defense News.

Trump’s surprise October post drew wide attention and raised concerns that the United States could abandon a 33 year moratorium on nuclear weapons testing.

“Because of other countries testing programs, I have instructed the Department of War to start testing our Nuclear Weapons on an equal basis,” Trump posted on TruthSocial. “That process will begin immediately,” he wrote.

The White House response to the president’s remarks has been interpreted in different ways, but the core question remains: how should the United States deter threats while protecting global norms that help prevent escalation?

In Malaysia, Defense Secretary Pete Hegseth emphasized that a credible deterrent must be the baseline of American security.

“The president was clear: We need to have a credible nuclear deterrent,” Hegseth said, “That is the baseline of our deterrence.” He also argued that resuming testing could be a responsible measure.

“Having understanding and resuming testing is a pretty responsible — very responsible — way to do that. I think it makes nuclear conflict less likely, if you know what you have and make sure it operates properly,” he said. The military would work with the Energy Department on this testing, he added.

Energy Secretary Chris Wright appeared on Fox News to clarify the scope of any tests.

He said, “The tests we’re talking about right now are system tests. 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 the appropriate geometry and they set up the nuclear explosion.”

When host Peter Doocy pressed, Wright reassured listeners, “No, no worries about that.” The conversation touched on a long arc in U.S. history, from the Trinity test in 1945 to the Nevada Test Site’s Divider in 1992, a period that defined a generation of weapons development and measurement.

Historians and defense experts note the United States carried out 1,054 nuclear tests over nearly half a century.

John Erath, senior policy director for the Center for Arms Control and Non-Proliferation, recalled, “The U.S. had conducted over 1,000 nuclear tests.” He explained that the United States once possessed more data than any other nation and used that advantage to guide policy and stockpile stewardship.

“We had all the data necessary to know how nuclear weapons work, to verify that U.S. nuclear weapons would work, and other people didn’t. So by stopping testing when we did, we sort of locked in an advantage in knowledge that persists to this day,” Erath said.

Supporters of the current path argue that today’s laboratories and vast computing power allow precise simulations of nuclear effects.

Wright contends that the nation can predict outcomes with great accuracy because, as he put it, “we can simulate incredibly accurately exactly what will happen in a nuclear explosion.”

He recalled, “And we can do that because in the ’60s, ‘70s and ‘80s, we did nuclear test explosions. We had them detailedly instrumented, and we measured exactly what happened. Now we simulate what were the conditions that delivered that, and as we change bomb designs, what will they deliver?”

Hans Kristensen of the Federation of American Scientists pointed to facilities like the Lawrence Livermore National Laboratory’s National Ignition Facility as the new frontier for maintaining the stockpile without full-scale blasts.

The facility’s description highlights a laser system generating extreme conditions to study a controlled thermonuclear reaction.

In this framework, the goal is to assure reliability through reflection rather than explosion, a perspective echoed by Erath who noted that subcritical testing can confirm component performance without triggering a nuclear yield.

The debate soon turns to modernization. The United States is pursuing upgrades such as the B61-13 gravity bomb and new warheads for the LGM-35A Sentinel and the Trident II D5 missiles.

Part of that work involves tests of a weapon’s critical subsystems, Erath said, but he stressed that “you don’t need to do an explosive mushroom cloud-and-crater kind of nuclear test.” He added that “the smaller-scale subcritical testing, and that has been happening.”

Still, if full-scale testing were resumed, the international consequences would be severe.

Erath warned that “the dominoes would fall,” and Kristensen warned that countries like China, India, and Pakistan would have substantial incentives to resume their own programs.

The global taboo against testing would crack, and nonproliferation would suffer a major blow. He noted that Russia and China have signaled a desire to reexamine their programs, whether or not they act, and warned that such moves would complicate alliance assurances and deterrence.

Those who fear the strategic ripple effects argue that credibility with allies relies on predictable policy and disciplined messaging.

The presidents and secretaries who guided these discussions insist that the United States must stay ahead and ensure a credible deterrent, while maintaining the leverage that has kept the peace since the end of the last century.

The conversation is ongoing, but one thing remains clear: this issue touches the core of national security, global norms, and the future of American leadership on the world stage.