Experts: Full nuclear weapons tests would backfire on US

Defense News, By Stephen Losey, 6 Nov 25,

Resuming full testing of nuclear weapons — as President Donald Trump called for last week — would be unnecessary, costly, undermine nonproliferation efforts, and empower the nation’s adversaries to use their own tests as intimidation, expertstold Defense News.

Trump’s unexpected announcement, which came in the form of an Oct. 29 social media post, surprised many nuclear specialists — and sparked concerns that the UnitedStates may end its 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.

When asked for comment about nuclear testing plans, the Pentagon’s public affairs office pointed to an Oct. 31 video of Defense Secretary Pete Hegseth in Malaysia, in which he said testing nuclear weapons is a responsible way to ensure the country has “the strongest, most capable nuclear arsenal so that we maintain peace through strength.”

“The president was clear: We need to have a credible nuclear deterrent,” Hegseth said, “That is the baseline of our deterrence.

“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.

Hegseth also said the military would work with the Energy Department on this testing.

Energy Secretary Chris Wright said on Fox News Nov. 2 that tests focusing on the subsystems of new nuclear weapons are already in the works, but he said the tests would not result in a full nuclear detonation………………………………………………………………………………………………………………………………………………………………..

“The U.S. had conducted over 1,000 nuclear tests,” Erath said Monday in an interview with Defense News. “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.”

Since then, U.S. nuclear testing has relied on computer simulations designed to predict how a weapon would respond if triggered.

Wright said on Fox News that the United States’ advanced laboratories and computing power devoted to nuclear weapons provide a major advantage over other nations.

“We can simulate incredibly accurately exactly what will happen in a nuclear explosion,” Wright said. “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, director of the nuclear information project at the Federation of American Scientists, speaking Monday to Defense News, pointed to the Lawrence Livermore National Laboratory’s National Ignition Facility in California as an example of the kind of state-of-the-art facilities that the U.S. developed for safe nuclear testing purposes……………………………………………………………………………

As the government modernizes and extends the life of aging weapons in its nuclear stockpile, through efforts such as the W80-4 life extension program, it uses experiments at places such as the NIF to determine whether the weapons will still react properly if used.

Those simulation capabilities obviate the need for any testing of existing, upgraded, or new weapons,Kristensen said.

“It’s just a fundamentally different situation for the United States,” he said.

The U.S. now is modernizing its nuclear forces by creating a new gravity bomb, the B61-13, and new warheads to go on the upcoming LGM-35A Sentinel intercontinental ballistic missile and the Trident II D5 missile.

Part of that work will involve tests of the warheads’ critical subsystems, Erath said.

He said, though, that is it not necessary to go through the entire process and trigger the nuclear reactions that create devastating blasts to know whether the weapon will work.

“What happens after the plutonium goes critical is well known,” Erath said, “So you don’t need to do an explosive mushroom cloud-and-crater kind of nuclear test.

“You can do the smaller-scale subcritical testing, and that has been happening.”

Rattling a house of dynamite?

If the United States shatters the taboo against nuclear tests it helped create, other nations are sure to follow with their own tests, Erath said. Once that happens and they start to gather more detailed information on their own nuclear devices, he said, they will start to catch up to America…………

In an interview with 60 Minutes that aired Sunday, Trump claimed without evidence that China and Russia have conducted clandestine nuclear weapons tests deep underground……………………………………………………………………………………………………

If the U.S. government were to proceed with full tests that explode nuclear weapons, Erath said, it would likely happen underground. That would minimize the environmental impact, he said, but not eliminate it entirely, because leaks can happen.

The diplomatic consequences and harm to nonproliferation efforts would be far more severe, Erath said. The United States would likely receive a storm of condemnation from other nations, he said.

With the global moratorium on nuclear weapons testing broken, Erath said, nations such as Russia, China, North Korea, India and Pakistan would likely follow Washington’s example…………………………………………………………..

“This kind of confusion and uncertainty undermines U.S. credibility with its allies,” Kristensen said. “They need to know if they can trust U.S. policies. … If the U.S. president now begins to signal that he’s interested in [nuclear testing] in some shape or form … it’s going to add to the pool of uncertainties [allies] have about what kind of partner the United States is now, and will be in the future.”…………………………………………………

Digging a hole deep enough for a nuclear bomb test would take months, Kristensen said — and finding the right digging equipment would be another challenge, since not many organizations have needed to dig such holes in the desert for a long time. Once the nuclear device is in there, it has to be sealed properly with materials such as gravel and concrete to keep radioactive materials from venting.

“They would have to build a whole tower over the hole in which they have this instrument package that would be lowered in there,” Kristensen said. “Those instruments would have to be designed by the nuclear laboratories to be able to do what it is that they want to record. There’s so many levels of this that have to fall into place.” https://www.defensenews.com/global/the-americas/2025/11/05/experts-full-nuclear-weapons-tests-would-backfire-on-us/

About Stephen Losey

Stephen Losey is the air warfare reporter for Defense News. He previously covered leadership and personnel issues at Air Force Times, and the Pentagon, special operations and air warfare at Military.com. He has traveled to the Middle East to cover U.S. Air Force operations.