What’s at Play in the 2018 House of Representatives Races

Our Latest 2018 House Prediction

Updated Jan. 10
191 Democrats
224 Republicans
20 Toss-Ups

The 2017 elections gave Democrats a sizable confidence boost. The party won both governors’ races, a lot of state legislative seats and local elections, on top of exceeding past performances regularly in the year’s special elections. Add to that a blockbuster fundraising season, which has seen almost three dozen Democratic challengers out-raise Republican incumbents in the third quarter of the year, and it’s easy to see why there’s rampant speculation that Democrats may retake the House of Representatives in 2018. But even if Democrats’ popularity is on the upswing, flipping the House won’t be easy: the party will need to defend 8 seats and gain another 24 to secure the chamber, or to look at it the other way, Republicans can lose 23 seats and still hold onto their majority.

Jump to the list of competitive seats.

To get a better sense of how the next election cycle may play out, we’ve pulled together analysis of the most competitive seats, relying on data from election analysis sites as well as the latest polling, approval ratings and party target lists. As of November, we’ve found 40 such competitive races. Of those, 32 are currently held by Republicans. But the battleground seats will inevitably change over the coming year, and if history is any guide, the shift will benefit the party not in the White House: In November of 2009, the Cook Political Report identified 50 competitive House races (rated toss-ups or “leans”), 37 in Democratic districts and 13 in Republican districts. In its final report just prior to the 2010 midterms, the competitive district battleground according to Cook had exactly doubled to 100 districts, 91 held by Democrats and just 9 by Republicans. In the end Republicans gained 63 seats.

The Current House

Of the 40 most competitive races, 32 are currently held by Republicans and eight by Democrats. Democrats will need at least 24 seats to retake the House. (One seat, PA-18, is currently vacant after Representative Tim Murphy resigned in October.)

What a Modest Midterm “Wave” Might Look Like

The president’s party almost always loses during the first midterm elections – and in fact, they lose big: an average of 25 seats. If Dems hit that average, it would be enough to give them a slight majority in the House. And that’s just the average; in 2010, thanks to extensive Republican fundraising and the grassroots rise of the tea party, Democrats lost a whopping 63 seats.

What Might Happen if Trump's Approval Rating Stays Low

Since 1946, parties whose president has an approval rating under 50 percent lose an average of 36 seats, and Trump has never even cleared 50 percent (he’s currently hovering around 35 percent). This 36-seat bump would be more than enough to push Democrats over the top.

But national trends alone can’t predict individual races, where the candidates bring their own set of factors to bear. Below, we go deep on the competitive races. Click on each district to learn more about the candidates and the range of factors that will influence the election, including how much money each side has raised, what presidential candidate their districts voted for, and whether challengers will face an incumbent or vie for an open seat. We also look at the influence of heated national issues, like Republicans’ votes for legislation to repeal and replace Obamacare. (Challengers in many races, including in California, Illinois, and Nebraska, have cited House members’ support for the Republican healthcare bill as motivation to enter the race.) And we took cues from the parties themselves, each of which have identified their own target lists of vulnerable candidates and flippable seats.

Competitive Seats: House of Representatives

Click on each candidate to learn more.

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Incumbent Competitive Analysis for the House 2018 Midterms
District Incumbent Party Margin of
Victory (2016)
Winner (2016)
Latest 2018

*Predictions based on a weighted average of election predictions by the three leading election analysis sites: Cooks Political Report, Inside Elections, and Sabato’s Crystal Ball.

Graphics, Design and Development by Ashley Wu, Terri Neal, and Skye Fradd

Tracking the Most Competitive 2018 House Races