Essentially the crushing (eventually by force of arms) of the revolutionary left.

An important part of Western pop-journalism’s denunciation of the cultural revolution is to confuse the issue of the revolution’s casualties. It’s said that “thousands were killed” and then as example the case of some prominent scientist or intellectual is given, who was denounced by the Red Guards and forced to make a self-criticism. So the impression is given that leftists massacred thousands of decent, upstanding intellectuals. But actually the great bulk of those who suffered in this way were the “ultra-leftists” themselves who fought rearguard actions against the army in 1968. They were the ones killed, they were the ones forced into the countryside by the millions.
http://www.thenorthstar.info/?p=9866