Here, one man can use the liberum veto to block anything he wants.
I speak, of course, of Senator Jim DeMint. With a comically easy re-election campaign against Alvin Greene ahead of him, he can do whatever he wants, and he's putting a hold on all legislation in the Senate that both parties haven't agreed to.
If you're looking for villains on the Democratic side here, they're the Senators who oppose sweeping procedural reform. People give Harry Reid a lot of crap for the fact that good stuff usually dies in the Senate, but really I think the problem is more with people like Chris Dodd who have a lot of power in the chamber and are tying his hands. As far as I can, Reid is doing the best he can surrounded by a bunch of powerful old men who care more about their Senatorial privileges than getting anything done.