[Rainier1789]

I imagine the left had no problem with the Nazis until they turned against Stalin and violated the Molotov-Ribbentrop pact.

[Maine Mariner]

You are correct. There was left wing opposition to the US entering WWII or even providing military aid to Great Britain, and other European countries until Germany invaded
the USSR on June 22, 1941 (Operation Barbarossa).

[Arthur McGowan]

Actually, the Party Line was anti-Hitler before the pact, pro-Hitler during it, and then anti-Hitler again. I forget who it was I was reading (not David Horowitz—he’s too young) but he was old enough to remember his Red Diaper teachers in the NYC schools, who became pro-Hitler overnight, then anti-Hitler overnight.