At this point, well over half the incumbent Democrats in Congress know their circumstances for a primary with precision. And most of them will by default be the Democratic nominee in their respective districts. That doesn’t mean there’s no electoral leverage over them whatsoever, but idle threats about primaries just look silly.

What does scrotal asymmetry have to do with Sarah Palin? At first, the answer might seem like a mystery and an enigma wrapped in a conundrum. But the real answer is within our grasp, and it reveals something about the unreality of American politics.