"Obama Won and I Helped!"

I've always been intrigued by the voter's paradox: the difficulty of explaining why you should vote, if there's just about no chance you will cast the deciding vote.  One way to go is to give up the idea that we vote to have an impact.  We can just capitulate and say the only reason to vote is for the enjoyment of being with our neighbors and participating in democracy.  Or some such. But that