THIS is the classiest post:

[S]o long as other classes continue to exist, the capitalist class in particular, the proletariat fights it (for with the coming of the proletariat to power, its enemies will not yet have disappeared, the old organization of society will not yet have disappeared), it must still use a measure of force, hence governmental measures; if it itself still remains a class and the economic conditions on which the class struggle and the existence of classes have not yet disappeared, they must be forcibly removed or transformed, and the process of their transformation must be forcibly accelerated.
          --Karl "Big Daddy" Marx, After The Revoltuion