8. Ohio — Republican Gov. John Kasich is term-limited. (9)

Both parties are trying to cull their primary fields ahead of the early May vote. The state GOP central committee endorsed state Attorney General Mike DeWine over Lt. Gov. Mary Taylor, but Taylor has vowed to stay in the race. (Rep. Jim Renacci switched to the Senate race last month, making it a two-way race between DeWine and Taylor.) Meanwhile, on the Democratic side, former Rep. Dennis Kucinich roiled the race when he entered the contest on the eve of the filing deadline. Kucinich, this week, was endorsed by the Bernie Sanders-aligned Our Revolution group, a surprising move since frontrunner Richard Cordray had been scooping up endorsements from former competitors and Sen. Elizabeth Warren. Cordray is still the favorite for the nomination, but he’s being forced to respond to the iconoclastic Kucinich.