Even more they believed that the fascist had to be tamed. First the German fascists, but then the root of it all, the US fascists with their Hitler support and their genocidal anti-socialist world-domination program, bringing fascism to the whole world. I wouldn't call that betrayal, you could rather argue that the US fascists betrayed the oldest democracy.

Even Oppenheimer, who was a stance Anti-Stalinist and the liberal under the fascist security clique, had the very same view and motivation. Just from the far right.

https://www.osti.gov/opennet/manhattan-project-history/Event... names many more.