I'm not from the US, but part of the "free world" elsewhere. So, I might overlook something important. However, I claim that the bipolarity of the US political system is major contributor to the present political blockade. Where I come from new parties pop up and others vanish all the time. This is not possible in the US.
Just consider our latest addition: the "Pirate Party" (yes, this is the name). They come straight out of the nerd culture and now they are finding out how that culture and its technology can be applied to politics, even in the parliament of a big city-state (Berlin). I am confident that this experiment will have an interesting outcome.
I'm afraid that this is no practical answer to the original question, but I would really like to suggest to put more flexibility into the US political system.