Voters will head to the polls in 12 states today, the biggest Election Day ahead of the 2012 cycle, and for campaign watchers, there’s plenty to keep an eye on tonight. Here are some races you’ll want to keep in mind:


Among other things, Ohio voters will be voting on whether to repeal a Republican measure that severely restricts collective-bargaining rights. Unions and the Democratic allies are optimistic about success, and a win here would be a major blow to the GOP’s larger anti-worker agenda.


In addition to a gubernatorial race that Lt. Gov. Phil Bryant (R) is expected to win with relative ease, voters in Mississippi will be voting on the “Personhood” measures that would ban abortions, birth control, in-vitro fertilization, stem-cell research, and treatment of ectopic pregnancies.


Gov. Steve Beshear (D) is expected to cruise to an easy victory, despite being a Democrat in a conservative state with a weak economy. Expect other Democratic incumbents to study his win closely in advance of 2012.


Voters in Maine will vote on restoring Election Day voter registration, and the left hopes to overcome an 11th-hour infusion of secretive, right-wing money into the state.


With just a couple of state senate victories, Republicans can reclaim a majority in the chamber, and do a fair amount of damage dominating state government for the first time since 2001.


In today’s only federal race, there will be a primary to see who runs in the U.S. House special election to replace former Rep. David Wu (D).


State Sen. Russell Pearce (R), who led the charge on the state’s anti-immigrant law, faces a recall election.

North Carolina

Charlotte Mayor Anthony Foxx (D) is expected to easily win a second term, solidifying his role as a rising star in Democratic politics.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.