When Presidents Trump and Xi meet at Mar-a-Lago on Thursday, they will bring a common conviction that the fates of their nations—especially on grand issues like war and peace—rest firmly in their hands. Each has vowed to make his respective country great again (what Xi called “the great rejuvenation of the Chinese nation”). And each believes that the vision and determination of a strong leader with an unyielding agenda shape events; not vice versa.

While it is merely coincidental, it is nonetheless fitting that their summit occurs on the precise centennial of the day another world leader who shared their convictions about leadership got mugged by reality.

After three years of pledging to stay out, the United States entered World War I on April 6, 1917. An ardent opponent of U.S. entanglement in what he called a “European war,” Woodrow Wilson had just five months earlier won reelection to a second term in a campaign  built on his success in keeping America out of war. But the brutal logic of events overseas eventually forced his hand. The lesson for Xi and Trump today as they contend with an increasingly brazen, nuclear-armed North Korea, is best captured in Leon Trotsky’s insight: “You may not be interested in war, but war is interested in you.”

Wilson’s arc from strident non-interventionism to a declaration of war begins with a phrase now laden with historical baggage: “America First.” Long before Trump used it to define his foreign policy, before even Charles Lindbergh made it the banner of his pre-World War II isolationism, Wilson made “America First” (along with the slogan “He kept us out of war”) a centerpiece of his 1916 campaign.

As Wilson saw it, “America First” initially provided the rationale for staying out of a deadly European war—and then, for entering it. ...