“A HOUSE of Dynamite”, Kathryn Bigelow’s film about an impending nuclear strike on America, explores the terror and uncertainty of a nuclear crisis. An intercontinental ballistic missile is heading for Chicago, but nobody knows whether North Korea, China or Russia fired it. Within minutes, the American president must decide whether to retaliate—picking from a menu of “rare”, medium” and “well-done” thermonuclear options—knowing that any could lead to four-way Armageddon.
This fictional fog of nuclear war is terrifying enough, even with a rational president in charge and a professional staff to advise him. But what of the real world in which Donald Trump, a mercurial president with sole authority to fire thousands of nukes, displays deep confusion about nuclear weapons and his national-security staff dares not set him straight?
On October 29th, just minutes before his summit in South Korea with China’s leader, Xi Jinping, Mr Trump indulged in a bit of nuclear braggadocio with a post on Truth Social announcing that he had ordered the Pentagon to “start testing” nuclear weapons immediately. On the face of it, Mr Trump was announcing that America would restart underground nuclear explosions in Nevada for the first time since 1992. But his post was so riddled with errors and inconsistencies that perhaps, some suggested, Mr Trump was thinking not of warheads but rather the means to deliver them.
A degree of calculated ambiguity has always been part of deterrence, for instance in leaving fuzzy the precise circumstances in which a country might use nuclear weapons. Thomas Schelling, a cold-war strategist, wrote about “the threat that leaves something to chance”. NATO rejects the idea of a “no first use” policy, for instance. And Russia’s nuclear threats have limited the military assistance that the West has provided Ukraine.
America’s nuclear policy has never been like Mr Trump’s erratic approach to tariffs and diplomacy, where threats and bluffs can sometimes be used to gain advantage. In nuclear matters ambiguity can be dangerous “when nobody knows what the president is talking about”, notes Eric Edelman, a former senior Pentagon official. It does not help that Mr Trump carelessly threw out his bombshell as the globe is entering a new nuclear age—one with an alarming mix of deepening great-power rivalry, nuclear threats by Russia, China’s rapid build-up, pressure for more countries to go nuclear and the loss of arms-control restraints with the expiry next year of New START, a treaty that limits America’s and Russia’s long-range nuclear weapons.
Mr Trump’s social-media post was a muddle from the opening line claiming that “the United States has more Nuclear Weapons than any other country”. The best open-source estimate, by the Federation of American Scientists, assesses that America has a stockpile of 5,177 warheads, against Russia’s 5,459. Mr Trump claimed that China “will be even within five years”, even though the Pentagon reckons it will have 1,000 warheads by 2030 and possibly 1,500 by 2035.
His command was the biggest headscratcher: “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.” The president cast the move as a response to the actions of hostile regimes. But if he was thinking about warheads the accusation made no sense: the only country known to have conducted explosive tests this century is North Korea, the last time in 2017. If Mr Trump was thinking about delivery systems, then the order was redundant: America regularly tests its ballistic missiles, most recently in May.
Perhaps, some speculate, Mr Trump had received fresh intelligence of Russian low-yield tests, which have long been suspected, but that seems too technical. Most probably, Mr Trump was irked by news that Russia had tested two new long-range “superweapons”—the Burevestnik, a nuclear-powered cruise missile, and Poseidon, a torpedo—but did not grasp the difference between testing warheads and delivery systems.
Mr Trump has yet to explain himself. On October 31st he insisted that America would conduct tests but did not say what sort: “You’ll find out very soon.” The national-security bureaucracy did not clarify matters. General Richard Correll, the administration’s nominee to become the new head of Strategic Command, in charge of fighting any nuclear war, suggested at a Senate hearing that the president may have been talking about delivery systems. Yet Pete Hegseth, the “war secretary”, seemed to be thinking of nuclear blasts when he said that “resuming testing” was a responsible act to ensure deterrence, and the Pentagon would be “moving out quickly”.
Mr Trump has a range of options before him. The best would be to clarify that he will not conduct explosive nuclear tests unless rivals do, but such backpedalling is unlikely. He could hasten the routine launch of a Minuteman II intercontinental ballistic missile, and leave it at that. A riskier step would be to order low-yield underground tests, though the benefit may not justify the blowback. The most dangerous would be to talk himself into full-scale explosive nuclear tests.
Most American nuclear experts, including Republican-leaning ones, argue that China has most to gain from a return to nuclear testing. That is because over the years it has conducted far fewer tests (45) than Russia (715) or America (1,030). American officials reckon they have the riches of historical data, and the supercomputers to model nuclear explosions, to ensure that America’s weapons are reliable for the foreseeable future. It could take years, and congressional funding, to resume underground tests.
Two risks are apparent in Mr Trump’s nuclear fog. One is that China or Russia will seize on his ambiguity to resume nuclear testing “because Trump has given them the excuse”, notes Mr Edelman. A second is that American hardliners take the president’s words as license to push for testing. His first administration toyed with the idea. It was endorsed last year by Mr Trump’s former national-security adviser, Robert O’Brien. Senator Tom Cotton, once regarded as a potential defence secretary, cited Mr Trump’s remarks to extol “the obvious benefits of such testing to ensure the stockpile is fully prepared and ready” and to “send a strong message of resolve and deterrence”.
And yet, as Ms Bigelow’s Netflix president learns, just being ready is not enough to avoid nuclear catastrophe; mistakes and miscalculations can be dangerous when, as he tells audiences, “we all built a house filled with dynamite […] but we kept on living in it”.
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