Caveat: This entry presents an unreported observation regarding the November election. It does not attempt the premature, but important, task of
analyzing specific races. I therefore accept the criticisms of the commenters that the title of this entry presents an unrealistic level of certainty. A better title would have been: "A Sign that the GOP May Gain Governors."
The Republican party, which currently holds a significant advantage in state governorships (28 versus 22), may actually widen its lead in November.
Here is a very interesting statistic: 5 out of the 7 "unpopular" governors (i.e. those who have higher disapproval than approval ratings) are Democrats:
Doyle (D-WI): 44 approve - 48 disapprove
Granholm (D-MI): 45-52
Blagojevich (D-IL): 44-52
Baldacci (D-ME): 39-55
Kulongoski (D-OR): 36-56
Schwarzenegger (R-CA): 36-61
Murkowski (R-AK): 29-65
On the other hand, one of the most vulnerable governor is a Republican from the largest state in the nation. Of course, this is only one observation and does not consider the larger question of incumbency.
Update: David, a perceptive commenter, encouraged me to consider the incumbency issue. 8 Republican governors are not seeking re-election (Arkansas, Colorado, Florida, Idaho, Massachusetts, Nevada, New York and Ohio) as opposed to only 1 Democrat (Iowa). This seems to change the situation dramatically, to the point where
Howard Dean and others are predicting large Democratic gains, resulting in a Democratic majority. However, 6 of those open-seat states elected Bush in 2004, although obviously some did so only narrowly.
Using the simplistic assumption that currently unpopular governors will lose and open seats will vote according to
2004 presidential patterns, the GOP would still gain 3 governorships, meaning that the current advantage of 6 more Republican governors would double, to 12.
A more realistic scenario, however, is that moderately vulnerable incumbents will win, and that the close 2004 elections will split evenly. If we define moderately vulnerable as those with a 5% approval deficit, the Republicans would gain 1.5 seats, meaning the current Republican advantage would increase from 6 to 9.
Only if we define vulnerable as those candidates with a 16% approval deficit do the Democrats break even, and actually gain 0.5 seats.
Update 2: I have come under significant attack because of my contrarian analysis, which varies with the leading experts such as Larry Sabato and the respected Congressional Quarterly site. See the comments for two major errors in Sabato's work and an element of silliness in Congressional Quarterly's analysis.