House Republicans are in trouble heading into 2018.

President Donald Trump’s unpopularity, voter distaste of Washington and a highly energized Democratic base have combined into a toxic brew for the GOP and its 24-seat House majority. A record number of Democratic candidates are piling into swing districts from Southern California to northern Maine and from the Florida Keys to suburban Seattle, and Republicans trail by double-digits in many national House polls.


But ultimately, the battle for the House is a district-by-district affair. And a handful of seats scattered across the country reveal the trends that will dominate those battleground races for the next year, including huge Democratic primaries, Republicans’ growing suburban problem, and the outbreak of sexual misconduct allegations roiling more and more campaigns every week.

Here are POLITICO’s 10 most important House races of 2018 — and why they matter in the battle for the House:

Illinois’ 6th District: Revenge of the suburbs

GOP Rep. Peter Roskam won reelection handily in 2016, but his Chicagoland district saw a big shift, with President Donald Trump losing it by 7 points after Mitt Romney carried the seat by 8 points in 2012. And since Trump took office, elections in Virginia, New Jersey and a handful of congressional special elections around the country have seen local candidates fall to or even below Trump’s levels in the suburbs.

That’s a big warning sign for Roskam and other Republicans in suburbs of New York, Los Angeles, Detroit, Kansas City and more heading into 2018. Democrats have to wade through a crowded primary before they face Roskam. Kelly Mazeski, who picked up an EMILY’s List endorsement and raised the most money last quarter, is leading the pack, though anything can happen in a field of seven candidates. But even a bruised Democratic opponent may not stem the tide against Roskam and other suburban congressmen.

“Increasingly socially progressive, suburban voters have been drifting away from the GOP for years,” said Ian Russell, former Democratic Congressional Campaign Committee deputy executive director. “Trump dramatically accelerated this movement, and the tax bill will only further alienate them.”

Morning Score newsletter Your guide to the permanent campaign — weekday mornings, in your inbox. Email Sign Up By signing up you agree to receive email newsletters or alerts from POLITICO. You can unsubscribe at any time. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Utah’s 4th District: The reach seats

Democrats are not just targeting suburban seats, though. Salt Lake County Mayor Ben McAdams is among a growing cadre of Democratic candidates hoping to turn Trump country blue, along with Paul Davis, a former candidate for governor of Kansas.

In Utah, McAdams won his first mayor’s race in 2012, when Mormon Republicans were out in force to back Mitt Romney. And while Romney got 60 percent in Salt Lake County, McAdams got 55 percent. “I have a reputation as someone who gets things done by working across party lines,” McAdams said, adding that he expects the same ticket-splitting in his bid against GOP Rep. Mia Love.

These campaigns will look different than some “resistance”-style Democratic candidates around the country. Davis kicked off his campaign for Kansas’ open 2nd District seat by saying he wouldn’t support Nancy Pelosi as speaker because “we need new leadership in both political parties,” he said. That gamble, which positions him outside national Democrats, hasn’t hurt him in Washington. The DCCC has already listed him as a top-tier candidate, and Minority Whip Steny Hoyer’s PAC donated to Davis’ campaign.

No district exemplifies the coming internecine fights quite like GOP Rep. Barbara Comstock’s, whose northern Virginia seat is trending increasingly blue. | J. Scott Applewhite/AP Photo

Virginia's 10th District: Enormous Democratic primaries

Trump inspired a wave of candidates to run for Congress, including a lot of first-timers who have nevertheless raised big money in 2017. Now, many of them are preparing to battle one another in crowded primaries that could leave the winners weakened and drained of resources.

No district exemplifies the coming internecine fights quite like GOP Rep. Barbara Comstock’s, whose Northern Virginia seat is trending increasingly blue. Five Democrats finished the last fundraising quarter with over $150,000 apiece and have established different bases of support. The Democratic veterans group VoteVets is backing Dan Helmer, while state legislators are supporting state Sen. Jennifer Wexton. Lindsey Davis Stover and Alison Friedman, both former Obama officials, have tapped those networks for help. Democrats argue that primaries gin up excitement and participation, but Republicans will be on watch for when these races inevitably get negative.

California’s 39th District: The most expensive race of 2018?

GOP Rep. Ed Royce’s district has never been a top Democratic target before — but Hillary Clinton carried it in 2016, and Democratic candidates have flooded in, including some who are spending their own personal fortunes.

Six candidates running in this diversifying Southern California seat raised more than $4.1 million in one quarter last year, and there are still more than five months to go until the primary. Two Democrats — Andy Thorburn, a health insurance executive, and Gil Cisneros, a former naval officer who won the lottery — are self-funding much of their bids, while Mai Khanh Tran, a physician, has been endorsed by EMILY’s List. Meanwhile, Royce, a committee chairman, has been stockpiling campaign money for years preparing for the possibility of a strong challenge.

All signs point to record spending here, as Democrats hope to chip into the Republican stronghold in suburban Southern California — and the cost of TV advertising in suburbs of major cities like Philadelphia, Seattle, Miami and Phoenix will drive up the price of campaigning in dozens of other districts around the country. So don’t forget your wallet.

Rep. Carlos Curbelo, who was first elected in 2014, weathered $6 million in outside spending against him in this blue-leaning seat last year by creating distance from President Donald Trump. | John Shinkle/POLITICO

Florida’s 26th District: Can a moderate Hispanic Republican survive Trump?

Hillary Clinton won this Miami enclave by 16 points, the largest margin in a district controlled by a Republican. Meanwhile, moderate Cuban-American Rep. Carlos Curbelo won it by just under 12 points. Curbelo, who was first elected in 2014, weathered $6 million in outside spending against him in this blue-leaning seat last year by creating distance from Trump.

But Democrats hope that distance will evaporate now that Trump is the head of his party and the GOP is forced to defend 23 districts that Trump lost in 2016 — starting with Curbelo’s. Democrat Debbie Mucarsel-Powell, who picked up an EMILY’s List endorsement, doesn’t face a contested primary, which felled Democrats’ favorite candidate last cycle. Whether Curbelo’s personal brand and efforts to separate from the president still work during the Trump administration will be a key question deciding the 2018 elections.

Minnesota’s 8th District: Democrats in Trumpland

There is no question Democrats will be on offense in 2018. But under the radar, Republicans are optimistic about competing for a handful of Democratic-held seats that Trump won handily during the last election.

Rep. Rick Nolan (D-Minn.) is used to this, having faced tough races in each of the last three elections. Some of his colleagues, like Pennsylvania Rep. Matt Cartwright, saw their districts turn sharply against their party in 2016 and will face tough challenges for the first time. Either way, their rural, predominantly white districts are quickly trending away from Democrats.

Nolan still takes a progressive posture on some policies, like supporting Medicare for all. “I’m confident about my view on all of those issues and I don’t retreat from them, even though you’re getting pressure to retreat,” Nolan said. And Republican Pete Stauber, a St. Louis County commissioner, beat Nolan in fundraising last quarter. Cartwright, who was first elected in 2012, hasn’t faced a serious challenger before, and now he’s up against John Chrin, who nearly outraised him last quarter. If Republicans can win a handful of these districts, it will make Democrats’ efforts to net 24 seats and retake the House all the more difficult.

Texas’ 7th District: Are you awake yet?

Rep. John Culberson (R-Texas) has won his last nine congressional races by more than 56 percent, but the ground is moving underneath him and all signs point to him not recognizing that yet. He hasn’t hired a full-time campaign manager, The New York Times reported. And last quarter, he was outraised by not one, but two Democratic challengers — Alex Triantaphyllis and Lizzie Pannill Fletcher.

“Culberson has not been engaged with this community,” Triantaphyllis said. “Republicans do have reason to be concerned.”

One of congressional Republicans’ big concerns heading into 2018 is whether candidates who have never faced a tough race before understand how bad the political environment is — and how it could end their careers. Culberson’s sluggishness mirrors former Florida Rep. John Mica, who also didn’t build out a campaign machinery to combat Stephanie Murphy, who beat him by 3 points last year.

Nevada’s 4th District: Sexual harassment in 2018

Three battleground seats were upended by sexual harassment scandals in the last month. Two leading Democratic candidates in Kansas and Pennsylvania dropped out of their primaries. Andrea Ramsey exited after a 2005 harassment suit surfaced, while former staffers accused state Sen. Daylin Leach of inappropriate touching. In Nevada, Rep. Ruben Kihuen said he wouldn’t run for reelection after a former campaign aide and a former lobbyist said that he sexually harassed them.

They’re still battleground seats in a year that favors Democrats, but they might be heavier lifts without an incumbent and the taint of sexual harassment scandals. More broadly, they could be just the first of many campaigns derailed by sexual misconduct over the next year.

New York’s 24th District: Who’s afraid of John Katko?

While Democrats have seen a flood of interested candidates in battleground districts around the country, there are still a few holes in the roster.

GOP Rep. John Katko’s seat has been a top Democratic target since he captured it in 2014, but he has not drawn a top-tier Democratic challenger for 2018 yet after huge victories in his last two races. Syracuse Mayor Stephanie Miner continues to toy with the idea, and she said she is reconsidering it since Katko supported the GOP tax bill. California Rep. David Valadao is another Clinton-district Republican who hasn’t seen the same glut of Democratic challengers as many of his colleagues.

Watch some holes in the Republican recruitment map, too: The Congressional Leadership Fund said it plans to target Iowa Rep. Dave Loebsack for the first time, after Trump carried his district last year, but no serious Republican contenders have launched bids against Loebsack yet.

Iowa’s 1st District: Democrats’ old path meets their new campaigns

Ever since Democrats lost the House majority in 2010, they’ve seen Iowa as a key piece of the path back. But the state has gotten only more Republican since then, with the GOP holding three of four House seats and Trump crushing Clinton in the 2016 presidential race.

In 2018, Abby Finkenauer — a state legislator who hails from a union family and is challenging GOP Rep. Rod Blum — is the Democrats' best hope to make a comeback in the state’s delegation. Trump won the seat by 3 points, but former President Barack Obama carried it twice before that. More critically, Democrats would love to diversify their chances of a House win beyond a suburban sweep, given how strong some Republican incumbents are in those districts. Finkenauer’s roots in the union community and renewed Democratic enthusiasm could put her over the top, but Blum and the GOP will hope that the party’s recent gains in blue-collar districts in Iowa, Wisconsin and elsewhere can withstand a tough political environment. Finkenauer is one of the Democrats' best hopes, but she faces a contested primary first.