The United States is the world leader in regime change, toppling 35 foreign heads over the past 120 years, by one reckoning. It’s a record built on a dangerous combination of unparalleled military might, a large group of perceived enemies—and a sunny self-confidence that has repeatedly proven mistaken. No one has shown himself more tempted by the power to unleash the world’s strongest army and economy to win arguments, take territory, smack down adversaries, and cow allies than President Donald