How Republicans Won the House

The president’s party has lost seats in almost every midterm election since the Civil War. This time was no different, with Republicans picking up at least six seats.

But Democrats avoided the steeper losses that are normal for the president’s party in midterm elections. The number of Democratic losses will most likely grow as the final outstanding races are called, but Democrats will still have lost fewer seats in 2022 than the president’s party has in most recent midterms.

Most districts shifted right

The 2022 midterms were the first elections after nationwide redistricting redrew the electoral map, making it difficult to compare House results across elections. But it is possible to understand partisan shifts at the district level by comparing the 2022 House results with the 2020 presidential vote within the new district boundaries.

Though Democrats held off a red wave, there was still a red ripple: In their districts, most 2022 Republican House candidates outperformed then-President Donald J. Trump’s 2020 election results.

In the chart below, each arrow shows the partisan shift in the 2022 House vote compared with the 2020 presidential vote. The red arrows represent districts where voters cast ballots for the Republican House candidate in 2022 by a higher margin than they did for Mr. Trump in the 2020 presidential election. Blue arrows represent districts that voted more Democratic in 2022 than they did for Joseph R. Biden in 2020.

State politics mattered in House races

How candidates fared differed significantly by state. Republicans performed extremely well in some states but fell short in others, especially in states with high-profile races for Senate or governor and in states where abortion was on the ballot.

In Florida, once a battleground state, Republican candidates outperformed Mr. Trump by an average margin of almost 12 points, even when they did not win. Gov. Ron DeSantis won re-election by nearly a 20-point margin. Florida districts saw among the biggest rightward shifts of any state, on average, compared with 2020.

New York districts saw a similarly pronounced rightward shift of more than 11 percentage points, on average. Abortion and democracy, critical issues for Democratic candidates nationwide, may have seemed less important to voters in New York, which has a strong Democratic majority in the State Legislature.

After a state court overturned a redistricting map drawn by Democrats, five New York congressional districts were rated by the Cook Political Report as tossups ahead of election night, meaning they could go to either party. All five went to Republicans.

Michigan, on the other hand, shifted meaningfully blue. Democrats won statewide races there and voters turned out in favor of ballot measures supporting abortion and voting rights. That support for Democrats also showed up in the House, where Michigan districts voted 0.2 points to the left, on average, compared with the 2020 presidential election.

Redistricting hurt some incumbent Democrats

In elections that come right after redistricting, a district’s boundaries may have changed significantly, and the district may represent a very different group of voters than before.

In some cases, new district shapes put incumbents at a disadvantage. Many of the Democratic incumbents who lost their seats were running in districts with very different shapes compared with two years ago.

In most of the districts where Democratic incumbents lost, redistricting caused the district’s underlying partisanship to shift to the right ahead of the election. A district that voted for Mr. Biden by 10 points in 2020 may have been redrawn to encompass an area that had voted Democratic by only two points, for example, meaning that redistricting alone caused the district to shift to the right.

One exception was Representative Sean Patrick Maloney, the five-term New York congressman and chair of the Democratic Congressional Campaign Committee, who chose to run in a new district that was redrawn to favor Democrats and still lost.

Still, redistricting was less responsible for Republican gains than a genuine shift to the right in many places. Take, for example, the five House districts where voters had supported Democratic candidates for president in at least the past two elections but chose Republican representatives this year.

Those Republican gains came largely in upstate New York and on Long Island, and in Oregon’s Fifth District, where a centrist Democratic incumbent had been unseated by a more liberal candidate in a primary.

Republicans also won a handful of the districts that Mr. Trump won in 2016 but lost in 2020, signaling a shift back to the right in many of those places.

The rightward shift in 2022 in many places most likely represents a change in political feelings over the last two years. But individual personalities in House races can also matter, and in some cases may have cost Republicans seats.

In Washington’s Third District, which voted for Mr. Trump in both of the past two elections, Democrat Marie Gluesenkamp Pérez won an upset over her Republican opponent, Joe Kent. Mr. Kent, who ousted the Republican incumbent in a primary challenge, had spoken at a rally supporting the Jan. 6 rioters and backed a national abortion ban.