Every two years, all the 435 seats in the U.S. House are up for election, but only a handful of races are truly competitive because of the way congressional districts get drawn.

Republicans currently hold 246 seats while Democrats hold 186, with three seats vacant pending special elections. Ballotpedia predicts only 23 of the races will be truly competitive on Nov. 8, not enough to turn the body over to the Democrats. The question is what will happen if Donald Trump is overwhelmingly defeated and whether that would trickle down the GOP ticket.

To reclaim the House, Democrats would need to pick up a net 32 seats. Here is a look at some of the most competitive races:

Arizona, 1st District

This race has no incumbent and pits Democrat Tom O’Halleran against Republican Pinal County Sheriff Paul Babeu, who made headlines in 2012 when he was forced to resign as the state chairman of Mitt Romney’s campaign amid charges he wanted a former boyfriend deported. A poll commissioned last week by the Democratic Congressional Campaign Committee released last week gives O’Halleran a 10-point edge. A poll by Babeu’s campaign indicates O’Halleran was just 3 points ahead.

darrell issa Incumbent Republican Rep. Darrell Issa (pictured in Washington, Dec. 9, 2014). Photo: Gary Cameron/Reuters

California, 49th District

Incumbent Republican Darrell Issa, who has spearheaded investigations of Hillary Clinton, is in a tight race with Democrat Douglas Applegate. Issa has been in Congress since 2000 and represents southern Orange County and western San Diego County. Issa is one of the wealthiest members of Congress, worth more than $355 million in 2012. He votes with the party on most legislation. Issa piled up impressive majorities in his earlier campaigns but a DCCC poll last month gave Applegate a 4-point edge.

Colorado, 6th District

Incumbent Republican Rep. Mike Coffman, who favors making English the nation’s official language, represents the most diverse district in Colorado. He faces Democrat Morgan Carroll, who was president of the state Senate. The contest could hinge on Hispanic turnout. RealClear Politics rates the contest a toss-up.

john mica Incumbent Rep. John Mica, R-Fla., (pictured during a House Oversight and Government Reform Committee, Oct. 6, 2008) is in a tight race with Stephanie Murphy. Photo: Jonathan Ernst/Reuters

Florida, 7th District

Incumbent Republican Rep. John L. Mica is seeking his 11th term in the House and faces a challenge by business professor and former national security specialist Stephanie Murphy, whose family immigrated from Vietnam. The House Majority PAC has poured $962,000 into Murphy’s campaign. A DCCC poll indicates Murphy is leading Mica 45 percent to 43 percent.

Florida, 26th District

This is a replay of the 2014 contest between Republican Carlos Curbelo and then-Rep. Joe Garcia. This time around, Curbelo is the incumbent and the race is tight. The DCCC has spent more than $2 million in hopes of reinstalling Garcia. Pollster Expedition Strategies gives Garcia a 47 percent to 46 percent lead over Curbelo but the margin widens to 48 percent to 40 percent when negative and positive messages are tested.

Illinois, 10th District

Incumbent Republican Bob Dold is facing former Democratic Rep. Brad Schneider in a replay of the 2014 contest. The north suburban Chicago district is one of the most competitive in the country and has been going back and forth between the parties since the 2010 census. Dold declined to endorse Trump but Schneider’s campaign has been trying to paint him as a down-the-line party member. The latest DCCC poll gives Schneider an 8-point edge over Dold.

Iowa, 1st District

Incumbent Republican Rep. Rod Blum, a member of the House Freedom Caucus, represents a district that voted for President Barack Obama twice. He faces Cedar Rapids City Councilwoman Monica Vernon. A GBA Strategies tracking poll indicates Vernon leads Blum, 48 percent to 47 percent.

Minnesota, 3rd District

Incumbent Republican Rep. Erik Paulsen represents a suburban district outside Minneapolis. He initially had been considered easy pickings by the Democrats, who have devoted $1.8 million to their bid to elect state Sen. Terri Bonoff. DCCC polling gives Bonoff a 2-point edge.

Nebraska, 2nd District

Rep. Brad Ashford is perhaps the most vulnerable Democratic incumbent, facing a challenge from Republican Don Bacon and Libertarian Steven Laird. In 2014, Ashford became the first Democrat sent to the House by Nebraska since 1994. Republicans have beefed up their registration effort this time around, signing up 13,342 more voters than the Democrats in the district. A Global Strategy Group poll in September indicated Ashford had a 10-point lead on Bacon, double the survey’s margin of error.

Nevada, 3rd District

This race is wide open and already has garnered more than $6.8 million in campaign spending. Democrat and computer programmer Jacky Rosen has the backing of retiring Sen. Harry Reid. He faces Republican Danny Tarkanian, the son of basketball coach Jerry Tarkanian. DCCC polling consistently has indicated Rosen in the lead, the latest poll showing he’s leading Tarkanian 44 percent to 37 percent.

scott garrett Rep. Scott Garrett, R-N.J. (pictured at the Reuters Financial Regulation Summit in Washington, April 28, 2014), is fighting for his political life against Democrat Josh Gottheimer. Photo: Gary Cameron/Reuters

New Jersey, 5th District

Incumbent Rep. Scott Garrett irritated his Republican colleagues last year by refusing to donate to the party’s campaign committee because it backs gay candidates. Challenger Josh Gottheimer, a former Clinton speechwriter, has been reminding donors and voters about the comments and also denouncing Garrett’s tendency to vote with the leadership. DCCC polling gives Gottheimer a 7-point lead on Garrett, 49 percent to 42 percent.

Virginia, 10th District

Incumbent Republican Rep. Barbara Comstock severed ties with Trump after release of the “Access Hollywood” tape in which he was heard bragging about forcing himself on women. She faces Democratic real estate developer LuAnn Bennett, who has been working to tie Comstock to Trump. The DCCC poll indicates Bennett has a 4-point lead on Comstock.