The last few days—as President Donald Trump has savaged America’s allies over trade, demanded that they readmit Russia to the G7, and embraced North Korean dictator Kim Jong Un—make something clear: Cold War conservatism is dead. What’s replacing it resembles less the foreign-policy outlook that has animated conservatives since World War II than the sentiment that prevailed before it.

In the 1920s, conservative Presidents Warren Harding, Calvin Coolidge, and Herbert Hoover rejected both binding alliances and the notion that America should make economic sacrifices to uphold the geopolitical order. They saw little difference between Britain and France, which were more democratic, and Germany, which was more authoritarian, and insisted that America remain independent from them all. They opposed Woodrow Wilson’s dream of requiring America to aid European nations threatened with aggression through the League of Nations. And, among some conservatives, this fear of binding international commitments continued well into the 1940s. As late as 1949, Ohio Senator Robert Taft—dubbed “Mr. Republican”—voted against the North Atlantic Treaty Organization because NATO, like the League, restrained America’s freedom of action. “It obligates us,” Taft warned, “to go to war if at any time during the next 20 years anyone makes an armed attack on any of the 12 nations.”