Updated November 1 to reflect changes in Ohio's gubernatorial race.

Since Governing last rated the 37 gubernatorial races on Oct. 18, a number of races have moved around a bit, but our overall assessment -- a net GOP gain of seven seats, with a possible range of three to 11 -- remains the same.

Two contests shifted significantly in the GOP's direction -- New Mexico, which moves from lean Republican to likely Republican, and Colorado, which shifts from likely Democratic to lean Democratic. Four races shifted in the Democrats' favor -- California, from tossup to lean Democratic; Maryland, from lean Democratic to likely Democratic; New York, from likely Democratic to safe Democratic; and Ohio from lean Republican to tossup. The rationale behind each of these shifts is explained in the ratings below.

An additional state shifted as well -- Rhode Island, where a three-candidate race is too volatile to pin down with much certainty. With this ranking, we're moving it from lean Democratic to tossup.

The list of gubernatorial races below works in two ways.

First, it categorizes every seat as safe Republican, likely Republican, lean Republican, tossup, lean Democratic, likely Democratic or safe Democratic.

Second, it rank-orders each seat by the likelihood of being won by a Republican, with one being most likely to be won by a Republican and 37 being most likely to be won by a Democrat.

Since the current breakdown is 26 Democrats, 23 Republicans and one Independent (former Republican Charlie Crist of Florida), even a disappointing night for the GOP should net the party a majority of gubernatorial seats. A strong night could leave the GOP with better than two-thirds of the seats.

A big factor in the Democrats' ability to stave off big GOP gains remains their ability to seize Republican-held seats such as those in California, Connecticut, Hawaii, Minnesota, Rhode Island and Vermont. If the wave boosts Republicans running in those states -- all of which are considered either tossups or lean Democratic states on our list -- then the gubernatorial picture will be grim indeed for the Democrats.

The rankings are based on discussions with a variety of sources on the national and the state level. The author has previously handicapped the governorships for Roll Call in the 2006 cycle and Stateline.org in the 2008 cycle.

Here is the ranking, along with brief comments on each rating category, and an explanation of the states that shifted categories.

Safe Republican (10)

Each of the states in this category are considered safe for the Republicans, but the exact ordering below is more subjective than it is for the other states on this list, since polling in these races is sparse or nonexistent.

1. Nebraska (R-held). Previous rating: 1.

2. Kansas (D-held). Previous rating: 3.

3. Wyoming (D-held). Previous rating: 4.

4. Tennessee (D-held). Previous rating: 6.

5. Oklahoma (D-held). Previous rating: 7.

6. South Dakota (R-held). Previous rating: 2.

7. Alabama (R-held). Previous rating: 8.

8. Alaska (R-held). Previous rating: 9.

9. Idaho (R-held). Previous rating: 5.

10. Utah (R-held). Previous rating: 10.

Likely Republican (6)

In each of these contests, the Republican candidate has maintained a consistent lead. Pennsylvania has seen a modest narrowing in the past week or so, but even there, Republican Tom Corbett remains a solid favorite against Democrat Dan Onorato.

11. Arizona (R-held). Previous rating: 11.

12. Nevada (R-held). Previous rating: 12.

13. Iowa (D-held). Previous rating: 13.

14. Michigan (D-held). Previous rating: 14.

15. New Mexico (D-held). Previous rating: 18 (shift from lean Republican). Democratic Lt. Gov. Diane Denish has consistently trailed Republican Susana Martinez, leading us to shift this race into the likely Republican category. An internal poll released by Denish showing a virtual dead heat strikes most observers as an outlier.

16. Pennsylvania (D-held). Previous rating: 15.

Lean Republican (5)

The possibility of a runoff in Georgia and the unusual strength of Texas Democratic nominee Bill White and South Carolina Democratic nominee Vincent Sheheen are the sole factors keeping these races out of the likely Republican category, where they would otherwise fit comfortably. The Wisconsin and Ohio races, which are being fought in more competitive territory, are decidedly more competitive, but in both states the Republican has a modest edge.

17. Georgia (R-held). Previous rating: 17.

18. Texas (R-held). Previous rating: 16.

19. South Carolina (R-held). Previous rating: 19.

20. Wisconsin (D-held). Previous rating: 20.

Tossup (7)

Each of these governorships is truly up for grabs, with no more than a finger on the scale for either party. Maine, Rhode Island and Massachusetts are complicated by having a credible independent candidate in the race.

21. Illinois (D-held). Previous rating: 22.

22. Maine (D-held). Previous rating: 23.

23. UPDATED NOVEMBER 1: Ohio (D-held). Previous rating: 21 (shift from lean Republican). Republican John Kasich has been ahead of incumbent Democratic Gov. Ted Strickland, narrowly, for most of the race, but recent polls have been especially close. So we're shifting the race from lean Republican to tossup.

24. Florida (I-held). Previous rating: 24.

25. Rhode Island (R-held). Previous rating: 29 (shift from lean Democratic). The contest has been jolted by President Barack Obama's decision not to endorse the Democrat, Frank Caprio, a decision that could benefit Independent candidate Lincoln Chafee (and which drove Caprio to lash out at the president). This race remains volatile, and it continues to evolve.

26. Oregon (D-held). Previous rating: 25.

27. Vermont (R-held). Previous rating: 26.

28. Massachusetts (D-held). Previous rating: 27.

Lean Democratic (6)

In each of these states, the Democratic candidate is generally considered to hold a lead -- narrowly in Hawaii and Minnesota, somewhat larger in New Hampshire and Connecticut and a bit more comfortably in California and Colorado.

29. Hawaii (R-held). Previous rating: 33.

30. Minnesota (R-held). Previous rating: 30.

31. New Hampshire (D-held). Previous rating: 31.

32. Connecticut (R-held). Previous rating: 32.

33. California (R-held). Previous rating: 28 (shift from tossup). Democrat Jerry Brown appears to have turned a corner against Republican Meg Whitman, with his poll margins increasing noticeably.

34. Colorado (D-held). Previous rating: 35 (shift from likely Democratic). The continuing implosion of Tea Party-backed Republican nominee Dan Maes has turned this into more of a two-man race between Denver Mayor John Hickenlooper, a Democrat, and independent Tom Tancredo, a strong critic of immigration. That's cut Hickenlooper's lead, but he's still the favorite to win.

Likely Democratic (2)

35. Maryland (D-held). Previous rating: 34 (shift from lean Democratic). A recent spate of polls shows Democrat Martin O'Malley successfully fending off his Republican challenger, former Gov. Bob Ehrlich -- a sign that the GOP wave is not ready to crash down fully on Maryland's shore.

36. Arkansas (D-held). Previous rating: 36.

Safe Democratic (1)

37. New York (D-held). Previous rating: 37 (shift from likely Democrat). Republican Tea Party favorite Carl Paladino torpedoed any chance he had of a serious run with an embarrassing series of gaffes and miscues. Democrat Andrew Cuomo is much safer than he was a few weeks ago, when Paladino burst onto the scene.