Marx was a philosopher without whom there never would have been a Lenin/Castro/Mao. Granted, his role in the political arena was limited, but I think the Manifesto constitutes a definite political agenda that was implemented. To go with the conservative chestnut, ideas have consequences, Marx's ideas certainly did.

I never thought of Affirmative Action as rebalancing. I have have always thought of it as promoting opportunity to succeed. Rather than claiming the universities "for the people" it allowed different types of people into the universities, what they did after that was up to them.