Something today's liberals can't do is cooperate with the left. Even über conservative "loyal to the crown" Churchill understood Britain would have to ally with the Soviets in order to beat the Germans. FDR was especially open to working with communists, whether Ho Chi Minh or Stalin, because of how difficult the invasion of Japan was going to be. If the US was to maintain its position as the colonial power in Asia, only total capitulation of Japan would allow for that to happen.

Liberals right now are completely incapable of cooperating with anything except the fascists who want to stab them in the back the moment they can get away with it. Liberals are working against their own interests because they're too high on their own supply of American exceptionalism. They think a trade war with China will favor the US. They're willing to cut themselves off from Latin America. Probably the most horrifying is the idea America can win a nuclear exchange against multiple countries.