“The Revolution”

... All political parties have some sort of ‘ vested interest ’ in their opponent’s unpopular moves. They live by them and are therefore liable to dwell upon, to emphasize, and even to look forward to them. They may even encourage the political mistakes of their opponents as long as they can do so without becoming involved in the responsibility for them. This, together with Engels’ theory, has led some Marxist parties to look forward to the political moves made by their opponents against democracy. Instead of fighting such moves tooth and nail, they were pleased to tell their followers : ‘ See what these people do. That is what they call democracy. That is what they call freedom and equality ! Remember it when the day of reckoning comes.’ (An ambiguous phrase which may refer to election day or to the day of revolution.) This policy of letting one’s opponents expose themselves must, if extended to moves against democracy, lead to disaster. It is a policy of talking big and doing nothing in the face of real and increasing danger to democratic institutions. It is a policy of talking war and acting peace; and it taught the fascists the invaluable method of talking peace and acting war.
pp. 163-164

Karl Popper, The Open Society and Its Enemies Vol. 2 - 1945