There's a long and interesting tribute to Herbert Marcuse, the anniversary of whose birth it was yesterday, on Doug Ireland's blog. Doug highlights Marcuse's Eros and Civilization, a work which, as I've indicated before, really impressed me when I first read it.
Doug also highlights Marcuse's concept of 'repressive tolerance'. Of this I'm more critical than he appears to be. Whatever may be said for it, Marcuse's argument under this heading includes the claim that liberal tolerance has the effect of absorbing oppositional movements, absorbing and appropriating thought which is critical of the prevailing, 'one-dimensional' order. It just has to be said about this effect of liberal tolerance, if it is one, that it's a much better problem for progressive movements to have to deal with than out-and-out repression and intolerance, as from dictatorial and totalitarian regimes.