Has anyone considered the idea that perhaps most politicians are quite apt at pleasing (manipulating) people and that they simply do what they do best when the audience shrinks to their previous target of convenience?
Absolutely. Great politicians are known for projecting the illusion to each group that their true loyalty is to the current audience, and all the policy moves that audience dislikes were forced by political pressure.
The following excerpt from an NPR story on TARP makes me feel that while the world is mad, I might have overestimated how much of that madness comes from our political leaders:
The import of this, as I see it, is that many lawmakers are pretty cognizant of the relevant issues, and that their irrational grandstanding is often a facade for the sake of the voters who think more tribally than quantitatively. The incentives are mad, but at least for now overt hypocrisy (and actual competence) is more common than sincere idiocy in Congress.
Of course, that's not completely reassuring, because if an important (but not immediately urgent) bill is unpopular, it's worth it for one party to actually oppose it and thereby gain political points. It's only in a genuine crisis that you'd see both parties actually do the right thing. (I leave it for your consideration whether TARP was indeed the right thing; but at least now I understand Harry Reid's claim that this was one of Washington's finest hours– a claim that Jon Stewart skewered mercilessly at the time.)