A couple weeks back, we deemed the Kentucky governor's race to be the nastiest of 2015. As it turns out, it's also perhaps the most competitive.

With the GOP primary being held Tuesday, all three top contenders -- state Agriculture Commissioner James Comer, former Louisville councilman Hal Heiner and businessman Matt Bevin -- are neck-and-neck in the polls. That's despite some leaving Comer for dead after a college girlfriend recently accused him of mental and physical abuse from back in their school days.

Some thought the blow would open the door to Bevin to close the gap between him and the erstwhile front-runners Comer and Heiner. And Bevin's chances have improved. But a SurveyUSA poll, conducted last week and after the Comer allegations surfaced, showed all three men between 25 percent and 27 percent -- a tie ballgame. And those in the know confirm it's wide open.

The implications are clear. Comer obviously has his issues and was once viewed as the most likely nominee, but six more months would be a lot of time to deal with the accusations (which were lodged just two weeks before a primary).

From there, Heiner is viewed as probably the strongest nominee, and has personal money to spend. Bevin, who lost a primary to Senate Majority Leader Mitch McConnell (R-Ky.) last year, is generally viewed as the weakest potential GOP nominee.

Waiting in the general election is state Attorney General Jack Conway (D). Republicans make no bones about their strategy here: tying Conway to President Obama and the national Democratic Party.

But Democrats have a popular governor here in two-termer Steve Beshear, and without a strong GOP nominee to press the partisan contrast, it's hard to call Republicans the clear favorites, despite Kentucky's conservative lean.

We'll find out a lot more Tuesday.

To the line! (As always, these are ranked from the most likely to change parties -- No. 1 -- to least-likely-but-still-potentially-competitive -- No. 5. There are 15 governor's races in 2015 and 2016, though, so any race on this list is a big one.)

5. New Hampshire (2016) (Democratic-held): We're still waiting on Gov. Maggie Hassan (D) to make a decision on running for Senate. Regardless, this race won't get off the ground for some time. Given only a two-year term is at stake, the campaigns tend to start a little later than in four-year-term states. This stays at No. 5, though, because it's a swing state, and it would be a top GOP pickup opportunity if Hassan runs for Senate. (Previous ranking: 5)

4. North Carolina (2016) (Republican-held): This is one of just two states that flipped between parties from 2008 to 2016, reverting back to Republicans. That's a pretty good barometer of how competitive it is. We would say the state leans right, given 2012 was a good Democratic year and Republicans still carried it, but the state is also changing quickly. And another four years means it will be different than the state that elected Gov. Pat McCrory (R) three years ago. He faces state Attorney General Roy Cooper (D) -- the guy Democrats have been waiting for -- in a race that polls very closely. (Previous ranking: 4)

3. Missouri (2016) (D): The big political news in Missouri these days is the resignation of state House speaker John Diehl after it was revealed that he exchanged sexual text messages with a state House intern who was in college. (Diehl is married with a family.) It's just the latest bit of drama as the state heads toward a 2016 governor's contest that will be between state Attorney General Chris Koster (D) and whoever emerges on the GOP side. Former U.S. attorney Catherine Hanaway was the front-runner, but former senator John Danforth (R-Mo.) just backed state Sen. Mike Parson, and businessman Jim John Brunner, who ran in the 2012 Senate primary, is considering running as well. (Previous ranking: 3)

2. Kentucky (2015) (D): See above. (Previous ranking: 2)

1. West Virginia (2016) (D): The big news here: Sen. Joe Manchin (D) opted not to run for his old job -- despite polling that showed he would have been a huge favorite. After that announcement, Jim Justice, the billionaire owner of the well-known Greenbrier resort (which is frequented by D.C. types on retreats), threw his hat in the ring. Potential GOP hopefuls include state Senate President Bill Cole, state Attorney General Patrick Morrisey and Rep. David McKinley. Manchin not running keeps this as the GOP's No. 1 pickup opportunity. Otherwise, it would probably have been off this list. (Previous ranking: 1)