He assumes that the moral and intellectual problems of the transformation of Society have been already solved — that a plan exists, and that nothing remains except to put it into operation. He assumes further that Society is divided into two parts: the proletariat who are converted to the plan, and the rest who for purely selfish reasons oppose it. He does not understand that no plan could win until it had first convinced many people, and that, if there really were a plan, it would draw support from many different quarters.

Keynes on Trotsky, 1933, via Brad deLong. Plus ça la change.