It’s been a remarkable few days for a man who once accused America’s “so-called allies” Japan and South Korea of “making billions screwing us.” A man who, as recently as last year, argued that “we’re better off” if both countries protected themselves from North Korea—by acquiring their own nuclear weapons if need be—rather than freeloading off U.S. military power. A guy who said, of a potential fight between Japan and North Korea, “Good luck, folks. Enjoy yourself.” When Donald Trump wrapped up his visit to Japan earlier this week, Orville Schell, a scholar of China and its neighbors since the 1970s, marveled, “In my lifetime, I’ve not seen the U.S.-Japan alliance more highlighted, vital, and well-fortified than now.” And in a speech in Seoul on Wednesday, Trump made a thundering commitment to defend South Korea. “The Trump administration hasn’t done anything that would weaken” the U.S.-South Korean alliance, Han Sung Joo, a former South Korean foreign minister and ambassador to the United States, told me shortly before Trump’s address. “The behavior of [North Korean leader] Kim Jong Un has only made the alliance stronger and [more] necessary.”