Harry Truman, Dwight Eisenhower, Ronald Reagan, and Bill Clinton forged different kinds of presidencies, but they had at at least two things in common.

All four saw their parties get battered in congressional elections.

And all four regained the presidency in part by using congressional opposition as a foil.

Many analysts are starting to think a Republican takeover of the U.S. House — and perhaps the Senate — could actually help President Obama when he seeks re-election in 2012.

All of this looks very depressing. American politics has been nothing more than a switch—it goes up or down—and it has done this switching predictably. There is, however, another politics at the end of the tunnel: the American system will eventually be Europeanized, there is no way around that. But for now, we are still caught in the gravity of a generation that saw this switching business as the terminal point of democratic participation.