Donald Trump has been obsessed with preventing a nuclear holocaust since he was a bumptious boy builder back in the 1980s. Back then Trump reportedly proposed, with typical grandiosity, that if President Ronald Reagan appointed him “plenipotentiary ambassador” he would end the Cold War “within one hour.”

Since then, Trump has rarely stopped talking about mitigating the danger of nuclear weapons. In his first presidential term, shortly before heading off to what would become an infamous 2018 summit with Vladimir Putin in Helsinki, Trump called nukes “the biggest problem in the world” and summed up for reporters what he hoped to accomplish: “No more nuclear weapons anywhere in the world.” Trump has repeatedly sounded the theme in his second term as well, warning over and over of “World War III.” In mid-February he declared: “There’s no reason for us to be building brand new nuclear weapons. We already have so many.”

So it’s more than a little curious to consider that, in less than three months as president, Trump has already set in motion the opposite trend: potentially the fastest and most dangerous acceleration of nuclear arms proliferation around the world since the early Cold War.

The new nuclear powers aren’t just the rogue nations that have long been the focus of U.S. concern, countries like Iran and North Korea. Increasingly, the nations considering going nuclear are longtime U.S. allies, from Germany to South Korea, Japan to Saudi Arabia. Faced with the threat of U.S. withdrawal from its defense commitments, more and more countries are now openly talking about embracing the bomb — and just as worrisome, actually deploying nukes if hostilities break out.