A crowded three-way race of GOP state lawmakers has developed to replace retiring Rep. Tom PetriTom PetriDozens of former GOP lawmakers announce opposition to Trump Dem bill would make student loan payments contingent on income Black box to combat medical malpractice MORE (R-Wis.), one of the few remaining centrist Republicans in the House, ahead of Tuesday's primary.

Wisconsin state Sen. Joe Leibham (R) raised the most money for the race and began with the most establishment support, but he has faced criticism for taking money from LIUNA, a union that backed the recall of Wisconsin Gov. Scott Walker (R), and his early lead seems to have slipped.

Businessman and first-term state legislator Duey Stroebel (R) has been self-funding his race and painting himself as the outsider, attacking both Leibham and state Sen. Glenn Grothman (R) as career politicians.

Grothman is the dark-horse candidate in the race. A hard-line conservative with a devoted local following and a penchant for controversial comments, he's attacked even Walker from the right on some issues and has agitated for conservative policy in the statehouse for decades.

Locals say any of the three could emerge as the nominee, and the fact that all three have been attacking one another makes it clear that none feel they can take the others for granted.

The district leans Republican, but Democrats believe if Grothman is the nominee, they could make a play for the seat. Winnebago County Executive Mark Harris (D) is Democrats' lone candidate for the seat.

Next door in Minnesota, Republicans will pick their candidate to replace retiring Rep. Michele BachmannMichele Bachmann'Real Housewives' producer 'begging' Conway to join cast Ex-rep admires furs amid PETA inaugural gala Why Republicans took aim at an ethics watchdog MORE (R-Minn.) in her conservative district. Former gubernatorial candidate Tom Emmer (R) won the state party nomination and is favored to win his primary against Anoka County Commissioner Rhonda Sivarajah (R), meaning he's likely headed to Congress next year.

Democrats will also pick their nominee to run an uphill race against Rep. Paul RyanPaul RyanIf Democrats want to take back the White House start now GOP grapples with how to handle town halls Leaked ObamaCare bill would defund Planned Parenthood MORE (R-Wis.). Filmmaker Amar Kaleka (D), whose father was murdered by a white supremacist in the 2012 Oak Creek Sikh temple shooting, is running against 2012 nominee Rob Zerban (D), who lost badly to Ryan last cycle in the Republican-leaning district.

Ryan also faces an opponent — Jeremy Ryan, a liberal activist whom Republicans tried to get thrown off the ballot.