In the 2024 election, four states voted Republican for president and elected a Democratic US senator: Arizona, Michigan, Nevada and Wisconsin. No state did the reverse, according to certified results in DataPorium data [1][2]. That compares with one split state in 2020 (Maine) and none in 2016 [1]. At the county level, 52 counties backed one party's presidential nominee and the other party's Senate nominee in 2024: 45 voted for Donald Trump and a Democratic Senate nominee, and 7 voted for Kamala Harris and a Republican Senate nominee [1].
Ticket splitting means voting for candidates of different parties on the same ballot. This article measures it with the margin: the Republican share of the vote minus the Democratic share, in percentage points. "R+3.2" means the Republican led by 3.2 points, and "D+3.2" means the Democrat led by 3.2 points. A state or county counts as split when its presidential margin and its Senate margin point to different parties.
How many states split their Senate and presidential votes?
DataPorium's split-ticket analysis compares each state's presidential margin with its Senate margin in the same election [1]. The last three presidential years give three different answers.
| Year | Senate races | States that split | Direction of the split |
|---|---|---|---|
| 2024 | 35 races in 33 states | 4: Arizona, Michigan, Nevada, Wisconsin | Republican for president, Democrat for Senate |
| 2020 | 35 races in 34 states | 1: Maine | Democrat for president, Republican for Senate |
| 2016 | 34 races in 34 states | 0 | None |
Source: DataPorium Election Results, certified results for 2016, 2020 and 2024 [1][2]. In 2024, California and Nebraska each held a regular and a special Senate election.
In 2020, Maine voted for Joe Biden by 9.1 points (D+9.1) and re-elected Republican Senator Susan Collins by 8.6 points (R+8.6) [1][7]. Georgia also showed a split in the November 2020 count: Biden led by 0.2 points, while Republican David Perdue led the regular Senate race by 1.8 points with 49.7% of the vote [1][8]. Georgia requires a majority, so that seat went to a January 2021 runoff, and it is now held by Democrat Jon Ossoff [9]. Counted by the final winner, 2020 had one split state.
Three 2024 races are not counted as Republican-versus-Democratic splits. In Maine and Vermont, both carried by Harris, independents Angus King and Bernie Sanders won re-election [1]. Pew Research Center counts both with the Democrats because they caucus with that party [10]. In Nebraska, which Trump carried, Republican Deb Fischer defeated Dan Osborn, who ran as an independent, by 6.7 points [1].
Over a longer span, splits used to be far more common. Pew counted a 59% mismatch rate between Senate and presidential results in 1986 and 18% in 2012. Its 2024 rate was nearly 12% (4 of 34 regular and special elections), the highest since the 2017-18 cycle [10].
Which states split in 2024, and by how much?
All four split states were carried by Trump by 5.5 points or less, and all four Senate races were decided by 2.4 points or less [2][3][4][5][6].
| State | President 2024 | Senate 2024 | Senate winner | Gap (points) |
|---|---|---|---|---|
| Arizona | R+5.5 | D+2.4 | Ruben Gallego (D) | 7.9 |
| Nevada | R+3.1 | D+1.7 | Jacky Rosen (D) | 4.8 |
| Michigan | R+1.4 | D+0.3 | Elissa Slotkin (D) | 1.8 |
| Wisconsin | R+0.9 | D+0.8 | Tammy Baldwin (D) | 1.7 |
Source: DataPorium Election Results, certified 2024 results [2][3][4][5][6]. The gap is the distance between the two margins, computed from unrounded figures.
The vote counts were close. Baldwin won the Wisconsin Senate race by 28,781 votes out of 3,390,787, and Slotkin won Michigan by 19,006 votes out of 5,577,187 [4][6]. In Arizona, Gallego won by 80,574 votes [3].
Splitting is the extreme case of a wider pattern: Senate nominees often ran ahead of or behind their party's presidential nominee without changing the winner. Among the 31 races in 2024 with a Democratic and a Republican nominee as the top two (California's two contests counted once), the Democratic nominee's margin was better than Harris's in 23, and the Republican nominee's margin was better than Trump's in 8 [1][2].
| Democratic nominee ran ahead | Gap (points) | Republican nominee ran ahead | Gap (points) |
|---|---|---|---|
| Montana (R+19.9 president, R+7.1 Senate) | 12.8 | Maryland (D+28.5 president, D+11.8 Senate) | 16.7 |
| Minnesota (D+4.2, D+15.7) | 11.5 | Utah (R+21.6, R+30.8) | 9.2 |
| Hawaii (D+23.1, D+32.7) | 9.6 | Massachusetts (D+25.2, D+19.8) | 5.4 |
| Arizona (R+5.5, D+2.4) | 7.9 | Wyoming (R+45.8, R+51.0) | 5.2 |
| Ohio (R+11.2, R+3.6) | 7.6 | Nebraska special (R+20.5, R+25.2) | 4.7 |
| Rhode Island (D+13.8, D+20.0) | 6.3 | Mississippi (R+22.9, R+25.6) | 2.7 |
Source: DataPorium Election Results, certified 2024 presidential and Senate results by state [1][2]. Gaps computed from unrounded margins.
Which counties split their tickets in 2024?
DataPorium data show 52 split counties in 19 states once the Maine, Vermont and Nebraska races with independent candidates are set aside [1]. Minnesota had the most (12), followed by Texas (7), Montana (6), New York (5) and Pennsylvania (3). In 45 of the 52, Trump led for president and the Democratic Senate nominee led for Senate; in the other 7, Harris led for president and the Republican Senate nominee led for Senate [1].
The largest split counties by votes cast are spread across 10 states. Together the 13 counties below cast 7,208,945 presidential votes [2].
| County | President 2024 | Senate 2024 | Presidential votes |
|---|---|---|---|
| Maricopa County, Arizona | R+3.5 | D+5.0 | 2,061,574 |
| Orange County, California | D+2.7 | R+1.0 | 1,390,965 |
| Tarrant County, Texas | R+5.1 | D+0.2 | 823,312 |
| Salt Lake County, Utah | D+10.2 | R+0.3 | 509,637 |
| Bucks County, Pennsylvania | R+0.1 | D+0.6 | 401,028 |
| Anne Arundel County, Maryland | D+13.8 | R+8.7 | 311,572 |
| Williamson County, Texas | R+2.4 | D+1.5 | 308,469 |
| Plymouth County, Massachusetts | D+8.8 | R+0.2 | 300,129 |
| Bristol County, Massachusetts | D+1.3 | R+0.8 | 278,017 |
| Hidalgo County, Texas | R+2.9 | D+6.6 | 217,265 |
| Anoka County, Minnesota | R+4.4 | D+7.5 | 210,481 |
| Passaic County, New Jersey | R+2.9 | D+2.7 | 202,767 |
| Jackson County, Missouri | R+4.1 | D+0.4 | 193,729 |
Source: DataPorium Election Results, certified 2024 presidential and Senate results by county [1][2]. Orange County, California, is compared with the full-term Senate race.
The largest, Maricopa County, gave Trump a 3.5-point lead and Gallego a 5.0-point lead, a gap of 8.5 points [13]. The split in Maricopa decided neither statewide result on its own, but it cast about 61% of Arizona's presidential vote [2][13]. Five of the 13 largest split counties went the other way: Orange County, Salt Lake County, Anne Arundel County, Plymouth County and Bristol County voted for Harris and for the Republican Senate nominee [1].
Where was the gap between Senate and president widest?
The widest county gaps came from two Senate races in which one nominee ran far ahead of the party's presidential ticket: Montana, where Democratic Senator Jon Tester lost by 7.1 points in a state Trump carried by 19.9 points, and Maryland, where Republican Larry Hogan lost by 11.8 points in a state Harris carried by 28.5 points [2][11][12].
| County | President 2024 | Senate 2024 | Gap (points) |
|---|---|---|---|
| Big Horn County, Montana | R+1.7 | D+27.5 | 29.2 |
| Blaine County, Montana | R+5.9 | D+20.3 | 26.2 |
| Roosevelt County, Montana | R+9.6 | D+15.5 | 25.1 |
| Norman County, Minnesota | R+22.2 | D+0.8 | 22.9 |
| Hill County, Montana | R+18.2 | D+3.2 | 21.4 |
| Anne Arundel County, Maryland | D+13.8 | R+8.7 | 22.5 |
| Frederick County, Maryland | D+8.7 | R+11.3 | 20.0 |
| Salt Lake County, Utah | D+10.2 | R+0.3 | 10.5 |
| Plymouth County, Massachusetts | D+8.8 | R+0.2 | 9.0 |
| Orange County, California | D+2.7 | R+1.0 | 3.7 |
Source: DataPorium Election Results, certified 2024 county results [1][2][11][12]. The first five rows are the widest Trump-and-Democratic-Senate splits; the last five are the widest of the seven Harris-and-Republican-Senate splits. Gaps computed from unrounded margins.
Why do voters split their tickets?
Election data cannot show why an individual voter chose different parties, but the patterns point to a few common explanations used by election analysts.
- Candidate-specific support. Senate nominees bring their own records, name recognition and local ties. Two of the four Democratic winners in Trump-carried states, Baldwin and Rosen, had won the same seats in 2018 [1][5][6].
- Third-party and independent candidates. Votes for other candidates change each race's margin. In Arizona's Senate race, a Green Party nominee received 2.3% [3].
- Roll-off. Some voters mark the presidential race and skip races further down the ballot. Arizona recorded 3,389,319 presidential votes and 3,347,964 Senate votes, 41,355 fewer [2][3].
- Close statewide races. When a state is near 50-50, a small gap between two races is enough to produce different winners, as in Michigan and Wisconsin, where the gaps were under 2 points [4][6].
Splits remain the exception. Pew Research Center found that 222 of 245 Senate contests since 2012, or 91%, were won by the party that carried the state in its most recent presidential race [10].
In 2024, four states and 52 counties chose different parties for president and US Senate, compared with one state in 2020 and none in 2016.
Frequently asked questions
What is split-ticket voting?
Split-ticket voting is choosing candidates from different parties on the same ballot, for example a Republican for president and a Democrat for Senate. In 2024, four states and 52 counties produced split results between those two races [1].
Which states voted for Trump and a Democratic senator in 2024?
Arizona, Michigan, Nevada and Wisconsin. Trump carried them by 0.9 to 5.5 points, while Democratic Senate nominees won by 0.3 to 2.4 points [2][3][4][5][6].
Did any state vote for Harris and a Republican senator in 2024?
No. No state carried by Harris elected a Republican senator in 2024, although seven counties, including Orange County, California, and Anne Arundel County, Maryland, did [1][10].
How common is ticket splitting in Senate races?
It has become less common. Pew Research Center put the mismatch rate at 59% in 1986, 18% in 2012 and nearly 12% in 2024, and none of the 34 Senate races in 2016 split [10].
Sources & References
- [1] DataPorium Election Results (Senate and presidential split-ticket analysis, 2016 to 2024)
- [2] DataPorium Election Results (2024 presidential results by state and county)
- [3] DataPorium Election Results (2024 US Senate results, Arizona)
- [4] DataPorium Election Results (2024 US Senate results, Michigan)
- [5] DataPorium Election Results (2024 US Senate results, Nevada)
- [6] DataPorium Election Results (2024 US Senate results, Wisconsin)
- [7] DataPorium Election Results (2020 US Senate results, Maine)
- [8] DataPorium Election Results (2020 US Senate results, Georgia)
- [9] U.S. Senate, Class II Senators (accessed October 13, 2026)
- [10] Pew Research Center, More states elected president and senator of different party in 2024 (November 26, 2024)
- [11] DataPorium Election Results (2024 US Senate results, Montana by county)
- [12] DataPorium Election Results (2024 US Senate results, Maryland by county)
- [13] DataPorium Election Results (Maricopa County, Arizona)
