The intro to this article by Matt Taibbi describes the current American political scene quite accurately and explains why I think the US is an empire in decline:

The really beautiful thing about the culture war, from an entertainment standpoint, is that it is fundamentally irresolvable. There isn’t a concrete set of issues involved, where in theory both sides could give in a little and find middle ground, reach some sort of compromise.
That’s because there are no issues at all. At the end of this decade what we call “politics” has devolved into a kind of ongoing, brainless soap opera about dueling cultural resentments and the really cool thing about it, if you’re a TV news producer or a talk radio host, is that you can build the next day’s news cycle meme around pretty much anything at all, no matter how irrelevant — like who’s wearing a flag lapel pin and who isn’t, who spent $150K worth of campaign funds on clothes and who didn’t, who wore a t-shirt calling someone a cunt and who didn’t, and who put a picture of a former Vice Presidential candidate in jogging shorts on his magazine cover (and who didn’t).
It doesn’t matter what the argument is about. What’s important is that once the argument starts, the two sides will automatically coalesce around the various instant-cocoa talking points and scream at each other until they’re blue in the face, or until the next argument starts.
And while some of us are old enough to remember that once upon a time, these arguments always had at least some sort of ideological flavor to them, i.e. the throwdowns were at least rooted in some sort of real political issue (war, taxes, immigration, etc.) we’ve now got a whole generation that is accustomed to screaming at cultural enemies as an end in itself, for the sheer dismal fun of it. Start fighting first, figure out the reasons later.

Depressing.