This Washington Post piece lays down early, heavy odds that Dubya gets a new lease at 1600 Pennsylvania Avenue:
Historically speaking, it should belong to President Bush. Since the presidential primary system became influential in 1952, an incumbent president has never lost a reelection bid if he did not face significant opposition in the primaries.
This is no nugget of political trivia. Political strategists and historians say an incumbent president's lack of primary opposition is a measure of how much support he has from his base of core supporters—and therefore how much leeway he has in appealing to the political center, the key to general election victory. Of course, historical patterns do not always repeat themselves, but Bush's strength among his base means the Democrats will have extraordinary difficulty dislodging him from office.