Socialism should be neither libertarian or authoritarian, it should just be itself, humanist, rationalist and democratic, if the state has a role to play then it should play it, if the state is a dangerous and harmful tool it should be changed from being such through gradual reform or temporary revolution.
Society is evolving toward socialism, ask any of the capitalists, revolutions are just periods of accelerated evolution, and as such might be undesirable, for instance if a revolution takes place in one country which is then cut of from others who disagree with this accelerated change hardship could result that would get blamed on the revolutionary praxis.
Liberalism is a better basis and partner for socialism than marxism.
P.S. Someones intercepting and inspecting my mail and a black helicopter hovered above my house for ten minutes the other night, I'm getting a bit suspiscious of something.