In reality, it was the Communists above all others who prevented revolution in Spain. Later, when the Right Wing forces were in full control, the Communists showed themselves willing to go a great deal further than the Liberals in hunting down revolutionary leaders.[Snip]
Between the Communists and those who claim to stand to the Left of them there is a real difference. The Communists hold that Fascism can be beaten by alliance with sections of the capitalist class (the Popular Front); their opponents hold that this maneuver simply gives Fascism new breeding-grounds. The question has got to be settled; to make the wrong decision may be to land ourselves in for centuries of semi-slavery.
I think you mean "written in 1943".