That was a quote from Don Haynes, Los Alamos National Laboratory (LANL) senior director at the Nevada National Security Sites, from an article published in LANL’s National Security Science magazine just 13 days ago on October 29, 2025.
The article goes on to explain, “Subcritical experiments allow researchers to evaluate the behavior of nuclear materials (usually plutonium) in combination with high explosives. This configuration mimics the fission stage of a modern nuclear weapon. However, subcrits remain below the threshold of reaching criticality. No critical mass is formed, and no self-sustaining nuclear chain reaction occurs -- there is no nuclear explosion.”
I’m going to quote more from the LANL article because it shows what subcritical testing the U.S. has been doing for years. For example, I wrote a Cipher Brief column in July 2021 that described subcrits this way: “Put simply, inside a steel container, a chemical high-explosive is detonated around a coin-like, small sample of plutonium [less than eight ounces] to simulate aspects of a nuclear explosion. No actual chain reaction or nuclear explosion occurs. But this contained detonation, with the assistance of computers, has helped scientists determine how plutonium behaves under the extreme pressures that do occur during detonation of a nuclear weapon.”
I further explained four years ago, “The main purpose, up to now, of subcritical experiments has been to identify and decrease uncertainties in the performance of currently deployed U.S. nuclear weapons, at a time when actual testing is not being done.”
I write this to deal with President Trump’s rather confused – and at times inaccurate -- series of recent statements about restarting U.S. nuclear testing. The President’s words have caused varied responses from his own officials – some of whom apparently did not want to appear correcting him. And the President’s words have gone so far as to encourage Russian President Vladimir Putin to convene a publicized Kremlin meeting last Wednesday where senior Russian national security officials discussed the possibility of Russia exploring the restart of their own full-scale underground nuclear testing.
To make it clear, the U.S. and Russia, by agreement, conducted their last underground nuclear tests in 1992. China did their last one in 1996. All three were signatories to the 1996 Comprehensive Nuclear Test Ban Treaty (CTBT), which prohibited “any nuclear weapon test explosion or any other nuclear explosion.” However, under the treaty, as the U.S. State Department explains on its website, the CTBT “does not prohibit subcritical experiments to help ensure the continued safety and reliability of nuclear weapons.”
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Russia has conducted at least 25 subcritical experiments at its Novaya Zemlya test site, according to past statements by U.S. Department of Energy (DOE) and Russian authorities. As of May 2024, the U.S. had conducted some 34 subcrits at the Nevada test site, according to DOE.
In 2022, a spokesperson for DOE’s National Nuclear Security Administration (NNSA), which manages the nuclear program, told Kyodo News that in June and September 2021, the U.S. conducted two subcritical tests, the first under the Biden administration. Three rounds of subcritical nuclear tests were conducted under the first Trump administration, and four rounds under Obama, according to other sources.
Currently, LANL has subcritical experiments scheduled into the year 2032, according to the recent National Security Science magazine article.
Meanwhile, the U.S. is developing several new warheads including the W93, which is intended for deployment on U.S. sub-launched ballistic missiles by 2040, according to NNSA. The NNSA website said of the W93, “Key nuclear components will be based on currently deployed and/or previously tested nuclear designs…The W93 will not require additional nuclear testing.”
Against that background, let’s review what President Trump has been saying, along with some of the responses.
The testing issue began with Trump in Korea on the evening of October 29. He had a meeting scheduled for 11 a.m. the next morning with Chinese Leader Xi Jinping. At 9 p.m., Trump sent off a message on his Truth Social public website that said: “The United States has more Nuclear Weapons than any other country. This was accomplished, including a complete update and renovation of existing weapons, during my First Term in office. Because of the tremendous destructive power, I HATED to do it, but had no choice! Russia is second, and China is a distant third, but will be even within 5 years. Because of other countries’ testing programs, I have instructed the Department of War to start testing our Nuclear Weapons on an equal basis. That process will begin immediately.”
What triggered Trump’s message has not yet been explained. Three days earlier, Putin, dressed in a military uniform, had publicly announced with some fanfare that Russia had successfully tested a nuclear-powered missile over the Arctic Ocean after years of development.
It may have been just competitiveness, but Trump was not clear what he was talking about when he wrote “testing our nuclear weapons.” Was he talking about nuclear delivery systems, as Putin had just been? Or was he talking about testing nuclear warheads or bombs?
If it were the latter, Russia actually has more nuclear weapons than the U.S., primarily because the U.S. has retired most of its tactical nuclear weapons. But if Trump meant strategic nuclear delivery systems, he was correct.
Then there was the ambiguity of what kind of testing Trump was talking about? He mentions instructing the Pentagon to “start testing,” which implied nuclear delivery systems, such as missiles, which the military controls. DOE’s NNSA tests the nuclear portion of warheads and bombs.
The next day, October 30, hours after the Xi meeting, Trump was flying back to the U.S. from Korea aboard Air Force One, and held an impromptu press conference. After 10 minutes of questions about meeting Xi, Trump was asked why he wrote the Truth Social piece about nuclear testing, Trump initially replied, “Well, that had nothing to do with them,” meaning the Chinese.
Trump went on, “It had to do with others.” He paused and then continued, “They seem to all be nuclear testing. We have more nuclear weapons than anybody. We don't do testing. You know, we've halted it years, many years ago, but with others doing testing, I think it's appropriate that we do.”
Since Trump mentioned the U.S. had halted the testing “years ago,” he created the impression at that moment he must have been thinking of explosive underground nuclear testing. When asked a follow-up question on where or when such testing would take place, Trump waved it off saying, “It will be announced. You know, we have test sites. It'll be announced.”
Having given the idea that he had ordered the resumption of explosive underground nuclear tests, it was no surprise that the next day, Friday, October 31, when Trump sat down at Mar-a-Lago with Norah O’Donnell for the 60 Minutes CBS News television program to be aired two days later.
Here I am using the CBS transcript of the entire one-hour, thirteen-minute Trump/O’Donnell interview and not the shorter, edited version shown on Sunday night, October 31.
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Well into the interview, after covering Trump’s Asia trip and meeting with China’s Xi, O’Donnell referred to his October 29, Truth Social message where he mentioned new nuclear testing and asked Trump, “What did you mean?”
Trump initially gave this wide-ranging response: “Well, we have more nuclear weapons than any other country. Russia's second. China's a very distant third, but they'll be even in five years. You know, they're making them rapidly, and I think we should do something about denuclearization, which is going to be some-- and I did actually discuss that with both President Putin and President Xi. Denuclearization's a very big thing. We have enough nuclear weapons to blow up the world 150 times. Russia has a lot of nuclear weapons, and China will have a lot. They have some. They have quite a bit, but…”
At that point, O’Donnell interrupted and asked specifically, “So why do we need to test our nuclear weapons?”
This time Trump answered, “Well, because you have to see how they work. You know, you do have to-- and the reason I'm saying-- testing is because Russia announced that they were going be doing a test. If you notice, North Korea's testing constantly. Other countries are testing. We're the only country that doesn't test, and I don’t want to be the only country that doesn't test.”
As I have pointed out above, other than North Korea’s six underground nuclear tests beginning in 2006 and ending in September 2017, there have been none confirmed, other than Russia’s acknowledged subcritical nuclear tests. So it again is unclear what Trump was mentioning.
Trump actually went on saying, “We have tremendous nuclear power that was given to us largely because when I was President (and I hated to do it, but you have to do it)-- I rebuilt the military during my first term. My first term was a tremendous success. We had the greatest economy in the history of our country.”
Trump then tried to turn the conversation to the economy, but O’Donnell brought him back to the subject by asking, “Are you saying that after more than 30 years, the United States is going to start detonating nuclear weapons for testing?”
This time Trump insisted, “I'm saying that we're going to test nuclear weapons like other countries do, yes,” and went on saying “Russia's testing nuclear weapons...And China's testing them too. You just don't know about it.”
Trump claimed the U.S. is an open society, but “they [Russia, China] don't go and tell you about it. And, you know, as powerful as they are, this is a big world. You don't necessarily know where they're testing. They test way underground where people don't know exactly what's happening with the test. You feel a little bit of a vibration. They test and we don't test. We have to test.”
That same day of the Trump/O’Donnell interview, October 30, Vice Admiral Richard Correll, Trump’s nominee to be head of Strategic Command, was having his confirmation hearing before the Senate Armed Services Committee. Asked if he knew whether Russia, China or any other country were doing explosive testing of nuclear warheads, Correll answered, “No.”
Asked whether Trump could have been talking about nuclear delivery systems, Correll said, “I don't have insight into the President's intent. I agree that could be an interpretation.”
On November 2, Energy Secretary Chris Wright appeared on Fox News and was asked about the new nuclear tests mentioned by the President. Wright replied, “I think the tests we're talking about right now are system tests. These are not nuclear explosions. These are what we call non-critical explosions.”
Asked whether the tests involve the existing stockpile weapons or new systems, Wright said, “The testing that we'll be doing is on new systems, and again these will be non-nuclear explosions.”
Wright explained that thanks to the nation’s national laboratories “the U.S. actually has a great advantage with our science and our computation power. We can simulate incredibly accurately exactly what will happen in a nuclear explosion. And we can do that because in the 60s, 70s, and 80s, we did nuclear test explosions. We had them detailed and 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. We have a reasonable advantage today in nuclear weapons design over all of our adversaries.”
On November 3, CIA Director John Ratcliffe came to Trump’s defense on the Russia, China testing issue, writing a Tweet on X saying the President “is right.” To back it up, Ratcliffe cited a May 2019 quote from then-Defense Intelligence Agency Director Lt. Gen. Robert Ashley Jr. saying Russia “probably” was conducting low-yield tests although Ashley did not claim to have specific evidence. He stated that Russia had the "capability" to conduct very low-yield nuclear tests.
Ratcliffe also cited a 2020 Wall Street Journal article that said the U.S. believed China may have secretly conducted a low-yield nuclear test based on circumstantial evidence, such as increased excavation, activity in containment chambers, and a lack of transparency at the site.
That same day, Sen. Tom Cotton, chairman of the Senate Intelligence Committee, put out his own Tweet on X saying, “After consultations with Director Ratcliffe and his team, they have confirmed to me that the CIA assesses that both Russia and China have conducted super-critical nuclear weapons tests in excess of the U.S. zero-yield standard. These tests are not historic and are part of their nuclear modernization programs.”
Despite all this Trumpian back and forth, I strongly doubt the U.S. will return to explosive nuclear testing, but rather remain with subcritical experiments as currently planned.
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