'nuff said. This is if you are interested in the political system and philosophy behind it, and not the ephemera of the moment. I like my info from primary sources first before I go and read secondary and tertiary sources. Find out not only exactly what is there, but why it is there, what the original arguments were about, and so on. Hint: the arguments are STILL about basically the same set of issues.
Your not going to want to read all of it, of course, so might I suggest something like this a nice set of primary sources, with some intros.
Also, as over-suggested as it is (for good reason), I'm gonna +1 on de Tocqueville! That is probably what to read after the primary sources, especially if you are looking at it from the outside (if you are very ambitious).
As for current politics, oh God! << contemplates jumping off a cliff >>. Unfortunately, if you know US history you know that this is more or less the permanent situation with the number of crazies and degree of stalemate fluctuating from decade to decade. Like it or not this is how our political system has been structured - to be an ongoing debate about not just laws, but the role (and degree) of government. It is all in the primary sources and goes right through our history. There is no guarantee that the participants are going to be rational, unselfish, participate in the debate and not just snipe from the outside (or even be sane). Both the strength and weakness of our system is that we usually get the politics we deserve. One main success out of this mess - we have only fought one actual war over these issues.
EDIT: on the other hand that may have given us more time to fight with others!