The midterm tide

2026 · The resultEvery Senate race moved one way

Set each Senate race against Trump’s 2024 margin in the same state. In all 31 races with both a Democrat and a Republican on the ballot, the Republican ran behind him: by 18 points in the median race, by 26 in Texas, and by less than one in Maine, where Susan Collins had long run ahead of her party, and lost anyway.

No midterm since at least 1978 has moved every race the same way. The closest were 1982 and 1986, when 29 races of 33 and of 34 moved against Ronald Reagan’s Republicans. Their median races moved further than this year’s, 26 and 28 points, but they came after his landslides of 10 and 18 points. Trump won by 1.5.

The South moved furthest: 20 points in the median Southern race, 16 elsewhere.

Signal 1 · Approval and the majorityUnpopular, with little to spare

Since 1946, nine presidents have gone into a midterm below 50% approval while their party ran the House. The six with 40 seats or fewer to spare over a majority all lost it: Truman in 1946, Clinton in 1994, George W. Bush in 2006, Obama in 2010, Trump in 2018 and Biden in 2022. The three with 45 or more kept it: Truman in 1950, Johnson in 1966 and Carter in 1978.

Trump went into this one at 33%, with two seats to spare.

2026Republicans lost the House, as the six before them did.

Signal 2 · The marginTwo seats to spare

Republicans can lose two House seats and keep the majority. Since 1830, four parties have gone into a midterm with four seats or fewer to spare. Three lost the House. The one that held on was George W. Bush’s, in 2002, a year after September 11, at 67% approval.

2026Republicans lost the House. By Wednesday morning they had lost at least 16 seats, with 60 races still uncalled.

Signal 3 · The Senate mapThe Senate map runs the other way

In the Senate, where the seats are matters more than how many are up. Since 2006 the president’s party has lost 13 of the 14 seats it defended in states the president had lost two years before. It gains only where the other party holds seats in his states: in 2018 Republicans lost 41 House seats and still gained two in the Senate, taking four of the ten Democratic seats in states Trump had won. In the five big waves since 1994, a state the president had carried by more than 10 points changed hands three times: Maine in 1994, Montana in 2006 and Wisconsin in 2010.

This year one Republican seat was in a state Harris won: Maine. Democrats needed four. After Maine, the other three would have to come from states Trump carried, where the closest was North Carolina, at 3 points, and the next Ohio, at 11.

They took Maine and North Carolina, then five seats in states Trump had carried by more than 10 points: Ohio, Iowa, Texas, Kansas and South Carolina. That is more such seats in one night than in the five big waves since 1994 together. They held Michigan and Georgia. Republicans kept Florida, at 13 points. Alaska, at 14, and Mississippi, at 23, were still being counted on Wednesday morning.

2026The map did not hold. Democrats kept all 13 of their seats and took 7 Republican ones, 5 of them in states Trump had carried by more than 10 points.

Signal 4 · The ballotDemocrats are running everywhere

Of the 435 House races in 2026, one has no Democrat on the ballot, by Ballotpedia’s count. That is the fewest in any election since at least 1976. In the four big waves since then, the party out of the White House left 17 seats or fewer unchallenged: 17 in 1994, 10 in 2006, 5 in 2010 and 4 in 2018. In the quiet midterms of 1990, 1998, 2002 and 2014 it left 36 to 45.

Across 12 midterms, this count has tracked the president’s losses more closely than his approval has: a correlation of 0.68, against 0.30. It is a sign of what candidates expected, not a cause. Strong challengers run when they think they can win.

2026The signal held. Democrats, who ran in 434 races, had won at least 231 seats by Wednesday morning, up from 215.

Signal 5 · The precedentOnly Grover Cleveland has been here

Trump is the second president to serve two terms that are not consecutive. The first, Grover Cleveland, faced a midterm in each. His Democrats lost 15 seats in 1886. In 1894, in a depression, they lost 125, the most any party has lost in a midterm. Trump’s Republicans lost 41 in 2018.

2026Still counting. Republicans had lost at least 16 seats by Wednesday morning; NBC News projected 43, near the 41 of Trump’s first midterm and far from Cleveland’s 125.

Signal 6 · The calendarThe House changes hands in midterms

Control of the House has changed nine times since 1946. The last time it changed in a presidential election was 1952. All six changes since came in midterms: 1954, 1994, 2006, 2010, 2018 and 2022.

2026The House changed hands in a midterm again, the seventh time in a row since 1952.

Signal 7 · The membersThe newest fall first

In 2010, 22 of the 38 Democrats first elected with Obama in 2008 who ran again lost, 58%. Of the Democrats elected before them, 16% lost. In 9 of the 11 midterms since 1982, the president’s first-term members lost at a higher rate than the rest of his party. Republicans elected 35 new members in 2024; 8 of them took seats Democrats had held.

Waves take the senior too: the Speaker, Tom Foley, with Dan Rostenkowski and Jack Brooks in 1994; Jim Oberstar, Ike Skelton and John Spratt in 2010; Pete Sessions in 2018.

2026Still counting. Which members lost is added once the district results are final.

And three that don’t matterWhat doesn’t decide it

Coattails

A president who brings many new members in with him is said to have more to lose. Since 1900, the House seats his party gained in his own election say almost nothing about what it lost two years later: a correlation of −0.10. Clinton in 1992 and Trump in 2016 lost House ground as they won, and still lost 54 and 41 seats in their midterms.

A surge in turnout

In 1994, 2006, 2010, 2014 and 2018, the states where turnout rose most from the midterm before did not swing harder against the president. Nor in 2026: the states that kept more of their 2024 turnout than they usually keep in a midterm swung no harder in the Senate, a correlation of −0.03.

A shrinking battlefield

The number of seats won by less than 10 points rises with each wave and falls after it, from 22 in 2004 to 89 in 2018. It has not been shrinking.

2 · Three seatsWhat it would take to hold the House

Republicans went in with 220 seats, two more than the 218 a majority needs. Since 1830, in 48 midterms with a party to score, the president’s party has lost fewer than three seats five times: 1834, 1902, 1934, 1998 and 2002.

Each dot below is one of those midterms, placed by the seats the president’s party gained or lost. Left of the dashed line, Republicans would lose the House this year.

3 · ApprovalUnpopular presidents always lose. How many is another matter

Gallup has asked about the president’s job before every midterm since 1938. All eleven presidents below 50% lost House seats, but the loss ran from 9 seats (Biden, 40%, in 2022) to 63 (Obama, 45%, in 2010), with 30 in the middle. Approval and seat change move together only loosely: a correlation of 0.30 across 22 midterms.

The dashed line is Trump in 2026, at 33%.

4 · TurnoutFewer people vote in the middle

Since 1840, every midterm has drawn fewer voters than the presidential elections on either side of it. Midterm turnout peaked at 71% of eligible voters in 1866, fell to 33% in 1926, and was down to 37% again in 2014. Then 2018 drew 50%, the most for a midterm since 1914.

5 · The SenateA looser rule

Only a third of the Senate is up each time, and which third decides a lot. Since 1934 the president’s party has held or gained Senate seats in 8 of 23 midterms. It lost four or more, what Republicans can’t lose this year, in 12.

Mostly the two chambers move together: since 1934 they went the same way in 18 of 23 midterms. When they part, the map explains it. In 1970, 1982 and 2018 the president’s party lost 12, 26 and 41 House seats and still gained Senate seats, because it was defending only 7, 12 and 9 of them. When it defended 20 or more, it lost Senate seats eight times in nine, seven on average.

This year Republicans defend 22 of the 35 seats up, counting the special elections in Ohio and Florida.

6 · The wavesThe biggest swings, by share of the House

In 1894, in a depression, Grover Cleveland’s Democrats went from 218 seats to 93, the most ever lost in a midterm. Measured as a share of the House, three of the five biggest waves came in the 19th century. The largest since then is 1922, and the largest of living memory is 1938.

7 · Where it brokeEach wave lands somewhere else

In 1994 the Democrats lost six seats in Washington alone, the Speaker’s among them. In 2010 they lost five each in New York, Ohio and Pennsylvania. In 2018 Republicans lost seven in California and four each in New Jersey and Pennsylvania. In 2006 and 2018 the Republicans didn’t gain a House seat in any state.

8 · One tideThe big waves are national

Take the districts that kept their lines and had both parties on the ballot both times. In 2010, 332 of 358 moved against the Democrats, 93%. In 1994, 2006, 2014 and 2018, at least four in five moved against the president’s party. In 1990 and 1998, about half did, and the House barely changed.

Nor do the same states lead each time. Measured against the national swing, how hard a state swung in one midterm says almost nothing about the next: the correlation from one to the next ran from −0.30 to 0.42, and averaged 0.03.

9 · The SouthTwo midterms remade the South

In 1976 Democrats held 81 of the 108 House seats in the eleven states of the old Confederacy, 75%. By 2024 they held 43 of 142, 30%. Two midterms under Democratic presidents did two thirds of that: 1994, from 62% to 49%, and 2010, from 45% to 28%.

10 · Who stays homeThe states that keep their voters

In the six midterms from 2002 to 2022, the average state drew 73% as many eligible voters as at the presidential election two years before. South Dakota kept 86%, and Hawaii, Oregon, Alaska and Montana more than 80%. Mississippi kept 59% and New Jersey 63%.

Three of the five that keep the fewest, Mississippi, New Jersey and Virginia, choose their governors in odd years, when there is no federal race at all. The five odd-year states kept 66% on average, the 34 states that choose a governor in the midterm 74%.

11 · 2026Where the House is decided

Republicans won 14 seats by less than five points in 2024. Thirteen are in states whose lines didn’t move: three in Pennsylvania, two each in Arizona and Iowa, one each in Alaska, Colorado, Michigan, Nebraska, Virginia and Wisconsin. Nine states with 173 seats, two in five, vote on different lines than in 2024, so their old margins say little.

12 · One ballotVoters stopped splitting their tickets

On the same day, in the same state, the Senate race and the House races used to go different ways. In 1994, 16 of the 34 states with a Senate race elected a senator from the party that lost the state’s House vote. In 2014 two did.

The gap between how the president’s party ran for the Senate and for the House in the same state averaged 8 to 13 points in every midterm from 1978 to 2006. In 2022 it was 3. The three splits of 2018, Democratic senators kept by Montana, Ohio and West Virginia, all went Republican in 2024. In 2022 four states split, all for Democratic senators: Arizona, Georgia, Nevada and Pennsylvania.

SourcesWhere the numbers come from

• House seats held by each party as each Congress opened, 1789 to 2025: Office of the Historian, US House of Representatives. The changes up to 1930 are worked out from it.
• House and Senate seat changes and Gallup approval for every midterm since 1934: The American Presidency Project, UC Santa Barbara. Its counts can differ by a seat from the House table, because seats change hands between an election and the day a Congress opens.
• Turnout of the voting-eligible population, 1789 to 2024, and the 2026 count: UF Election Lab, Michael McDonald, with Walter Dean Burnham’s estimates before 1948.
• Every House race by district, 1976 to 2024, for part two: MIT Election Data and Science Lab. Seats by state and the district swings are worked out from it; its seat totals come within a seat or two of the House’s own count of each election, so part two’s figures can differ by that much from part one’s. Turnout by state, 1980 to 2024: the UF Election Lab, with votes for the highest office standing in where a state reported no total of ballots before 2010.
• Every Senate race by state, 1976 to 2024: MIT Election Data and Science Lab. Georgia’s December runoffs decide who won; the vote shares are from November.
• States voting on new House lines in 2026: PolicyMap’s redistricting tracker, as of 28 September 2026, checked against Voting Rights Lab.
• Which party counts as the president’s before 1934 is the author’s reading. 1842 is counted for the Whigs, who elected John Tyler and expelled him a year later. Nine states vote on different House lines in 2026 than in 2024, so some of this year’s change was set before a vote was cast.