President Donald Trump is confused. Just moments before he was to meet with China’s President Xi Jinping, he posted a baffling message on his Truth Social site, claiming the U.S. would “immediately” resume the testing of nuclear weapons.
No one knew what he meant or why he was saying it.
Our knowledge is so deep that in 1992, we stopped testing. All other countries followed suit.
“Because of other countries testing programs [sic], I have instructed the Department of War to start testing our Nuclear Weapons on an equal basis,” Trump said, “That process will begin immediately.” When questioned later by reporters aboard Air Force One, he added: “We don’t do testing. We’ve halted it years, many years ago. But with others doing testing, I think it’s appropriate that we do also.”
That was hardly clarifying. Did he actually mean that the U.S. would resume exploding nuclear weapons at the old Nevada test site, something we have not done in more than 30 years? Or was he just reacting to Russian tests this week of a long-range cruise missile and an underwater drone?
To paraphrase Bill Clinton, it depends on what your definition of “nuclear” is.
The U.S. has conducted 1,054 explosive tests of nuclear weapons beginning with the world’s very first test of an atomic bomb in 1945. This is more than all other nations combined have exploded. As a result, the nation has a vast scientific understanding of the dynamics of nuclear fission (the splitting of atoms), nuclear fusion (the fusing of atoms) and the complex hydrodynamics of the hot plasma created in the first microseconds of a nuclear detonation.
Our knowledge is so deep that in 1992, we stopped testing. All other countries followed suit.
In 1996, the nations of the world, led by the U.S., negotiated the Comprehensive Nuclear-Test-Ban Treaty, or CTBT, banning nuclear explosive tests worldwide. One hundred and eighty-seven nations have signed the accord. No nation has tested nuclear weapons in this century, save for North Korea, which conducted six tests between 2006 and 2017. Those tests are one of the reasons North Korea is considered a rogue state, outside of international norms.
Using that data and ever-advancing supercomputers, we can now simulate nuclear explosions without an actual physical explosion. We conduct “sub-critical” experiments involving nuclear materials that stop just short of a full chain-reaction. The directors of our national weapons laboratories annually certify that the more than 5,000 nuclear weapons in our stockpile are safe, reliable and effective.
Although fiercely contested at the time — and still not ratified by the Senate — the test ban treaty ended the radiation poisoning of people near or down-wind from tests in Nevada and the South Pacific. It’s no wonder that members of Nevada’s congressional delegation reacted sharply to Trump’s threat.
Banning nuclear tests was not just the right moral and humane choice, but it also locked in an American advantage in nuclear knowledge.
“Absolutely not,” said Rep. Dina Titus, D-Nev., who vowed to introduce her bill to prevent a resumption of nuclear testing. Sen. Jacky Rosen, D-Nev., was equally firm, “This directly contradicts the commitments I secured from Trump nominees — and the opinion of Administration officials who certify our nuclear stockpile — who’ve told me explosive nuclear testing would not happen and is unnecessary. I’ll fight to stop this.”
Banning nuclear tests was not just the right moral and humane choice, but it also locked in an American advantage in nuclear knowledge. Resuming nuclear testing would allow other nations to catch up. If Trump began testing, other nations would quickly follow.
Russian spokesman Dmitry Peskov dryly responded to Trump, “Until now, we were not aware that anyone was testing anything.” He added, “But I want to recall President Putin’s statement, which has been repeated many times: that, of course, if someone abandons the moratorium, Russia will act accordingly.” China — which conducted only 45 test explosions, and none since 1996 — would leap at the chance to develop new nuclear weapons and experiment with new designs. India and Pakistan would certainly follow. Even Israel, which has never admitted to possessing nuclear weapons, though it is widely believed to have a small arsenal, might join the nuclear testing parade. Trump is poised to make nuclear testing great again — all across the world. Does Trump understand this? When he says “immediately,” does he understand that the Nevada test site has been closed for more than 30 years? That it would take almost three years to refurbish the facility — now known as the Nevada National Security Site — and get it in shape to explode weapons again? Does he even know that the cruise missile and underwater drone that Russia tested did not carry nuclear warheads? That they were tests of experimental delivery vehicles with small nuclear reactors providing propulsion, but that they did not carry nuclear warheads? He may not. Trump’s knowledge of nuclear issues is alarmingly thin. His purges of top scientists, generals and experienced national security experts have left him dangerously ill-advised. It is not as if Secretary of “War” Pete Hegseth can help. Maybe this was just a boss move, Trump’s attempt to assert male dominance as he met a powerful rival. Let us hope it was just a rhetorical flex. But it may not be. Nuclear hawks in the Pentagon and conservative bastions such as the Heritage Foundation have long pushed for restarting nuclear tests — including as part of its Project 2025 policy blueprint. They may have gotten to Trump. As MSNBC host Lawrence O’Donnell might say, the most profoundly ignorant president in American history may have just kicked off a new, treacherous nuclear arms race — and not even realize what he has done.
Joseph Cirincione
Joseph Cirincione is the vice chair of the Center for International Policy Board of Directors. 
