The real guarantee of freedom is an equilibrium of social forces in conflict, not the triumph of any one force. In trying to build, or defend, a free society, our first concern should be to make sure that no one gang or group - neither the proletariat, nor the capitalists, nor the landowners, nor the bankers, nor the army, nor the church, nor the state itself - shall have unlimited power.

Reflections on the Failure of Socialism (1955)