As World War II raged in Europe, Republicans initially opposed U.S. involvement even as proponents argued that helping allies would prevent direct aggression toward the U.S. — the same argument used today to support Ukraine. President Franklin D. Roosevelt, who supported involvement, found creative ways to overcome isolationist sentiment in the GOP. In 1941 Roosevelt proposed the Lend-Lease Act, a way to help U.S. allies, especially Britain, in the war without becoming directly involved by lending military aid to nations he thought needed it. Only two dozen Republicans in the House supported the Lend-Lease Act. In the Senate, 10 Republicans — one-third of the conference — backed it. (Twenty-two Senate Republicans backed the military aid package two weeks ago — about 45 percent of the conference, which is far less than the share of Republicans who supported previous iterations of funding for Ukraine.) Weeks later, the Japanese attacked Pearl Harbor, forcing the U.S. into the war. The attack sidelined the isolationist element of the party, but it didn’t go away. After the war, Sen. Robert Taft, an influential Republican from Ohio, opposed the creation of NATO. After his loss to Dwight D. Eisenhower in the 1952 Republican presidential primary, the isolationism string of the party went mostly dormant (or at least mostly ignored) until recently.

“It’s always hard to convince Americans about things overseas. That was true before Pearl Harbor and I can understand that,” Senate Minority Leader Mitch McConnell (R-Ky.), a strong proponent of defending Ukraine against Russia, told our colleague Liz Goodwin in a recent interview. “I think this is the most important thing going on right in the world.” McConnell said his father sent letters to his mom from the front lines of World War II, warning that Russia would continue to be a threat. “He proved to be accurate,” McConnell said of his father. John E. Herbst, former U.S. ambassador to Ukraine, attended the Munich conference and said he compared prewar isolationism with similar sentiments today in the meetings he attended. “This is a critical moment, like in the late ’30s,” he told us. “We can’t ignore the danger.”