The difference is that Liberals fundamentally accept the system of capital and empire as it is, and hope only to limit excesses here and there; Radicals want to go to the root of things, to upend the system of injustice itself, not merely the extreme symptoms. We see the choice before us as between Chaos or Community, Barbarism or Socialism.
I like this short video. Thanks to Bob Tom for sending it my way.
Bill Ayers 