Maine · Senate
election 2026-11-03 · forecast as of 2026-10-01 · margins and probabilities are for Troy Jackson
Who is running?
Troy Jackson (Democratic), Susan Collins (Republican). The margin below is Troy Jackson minus the other candidate in the main contest; the rest are on the ballot and not in it.
The race, in brief
Maine elects a U.S. senator on November 3, 2026, by ranked-choice voting. Republican Susan Collins, first elected in 1996, seeks a sixth term. The text records that Maine has voted for every Democratic presidential nominee since 1992, that Harris carried it by about seven points in 2024, and that Collins beat Sara Gideon by nine points in 2020 while Biden carried the state by about nine. Democrats have not won a Senate race in Maine since 1988. The state profile gives a median age of 44.8 and a college share of 0.4.
Collins was unopposed in the primary with 126,398 votes. Graham Platner won the Democratic primary with 72.1% but withdrew in July after a rape allegation and other accusations. A party convention on July 25 chose Troy Jackson, former president of the Maine Senate (2018–2024), over Saundra Pelletier, 566–5. As of June 30, 2026 Collins had raised $18,930,078 with $11,038,115 on hand; Jackson's line shows $0, filed before his nomination.
Seven raters listed call the race a Tossup, including the Cook Political Report (September 23, 2026) and Sabato's Crystal Ball (September 22, 2026); The Economist, FiftyPlusOne, Silver Bulletin and Split Ticket list it as 'flip'. The text's polling average is Jackson 47.5%, Collins 46.0%. The latest polls include co/efficient (R) (September 28–30, 2026) at Collins 48%, Jackson 46%; NYT/Siena (September 15–22, 2026) at Collins 49%, Jackson 46%; and the University of New Hampshire (September 17–21, 2026) at Jackson 51%, Collins 47%.
A paragraph quoting a model forecast from the day this brief was written is omitted; the current forecast is at the top of this page.
The facts, each beside its sentence
Republican incumbent Susan Collins is seeking a sixth term. She is being challenged by Democratic former state Senate president Troy Jackson.
Incumbent Republican U.S. senator Susan Collins is running for re-election to a sixth term.
Jackson was chosen to replace Platner via a nominating convention held on July 25.
In the June 9 primaries, Collins was the only candidate to qualify for the Republican nomination.
Troy Jackson, former president of the Maine Senate (2018–2024), candidate for ME-02 in 2014, and candidate for governor in 2026
Susan Collins, incumbent U.S. senator (1997–present)
Maine has voted for every Democratic presidential nominee since 1992, and Democratic nominee Kamala Harris defeated Republican nominee Donald Trump by approximately seven percentage points in the 2024 United States presidential election in Maine.
In 2020, despite almost all polls and analysts predicting that she would lose her re-election bid, Collins defeated Democratic nominee Sara Gideon by a nine-point margin.
Jackson won the convention vote over Pelletier, 566–5.
The Cook Political Report Tossup September 23, 2026 Decision Desk HQ Tossup September 25, 2026 The Economist flip September 26, 2026
| Susan Collins (R) $18,930,078 $9,187,155 $11,038,115
On July 8, Platner announced that he would drop out of the race, filing his withdrawal two days later.
co/efficient (R) September 28–30, 2026 1,240 (LV) ±2.8% |48% 46%
The election will be conducted with ranked-choice voting.
Democrats have not won a Senate election in Maine since 1988.
No political party in Maine had replaced their nominee in any prior election.
Not in the source: facts.candidates marks Susan Collins as incumbent: false, but the text names her the incumbent; the facts row looks wrong.; facts.forecast carries no basis field.; No finance report for Jackson after his July 25 nomination; the June 30 report shows $0.; The text does not explain what raters mean by 'flip'.; Endorsement sections are empty in the text.
Read from the district's section of Wikipedia's state page (CC BY-SA), archived as ee93988f47b9; written by claude-fable-5-1 (batch reader) on 2026-09-30 and checked mechanically: every quote occurs verbatim in the archived text, every number in the brief occurs in the inputs. No probability here is the reader's.
Who holds the seat now
Susan M. Collins (Republican), in this chamber since 1997, 5 terms, class 2 (term ends 2027). Committees: Senate Committee on Appropriations (Chairman); Senate Committee on Health, Education, Labor, and Pensions; Senate Select Committee on Intelligence.
Angus S. King, Jr. (Independent), in this chamber since 2013, 3 terms, class 1 (term ends 2031). Committees: Senate Committee on Armed Services; Senate Committee on Energy and Natural Resources; Senate Committee on Veterans' Affairs; Senate Select Committee on Intelligence.
From the congress-legislators dataset (CC0), archived as ae8cb9477c48. For a Senate race this lists both of the state's senators; the one whose term ends in the election year holds the seat on the ballot. For a House district redrawn for 2026 it is the member elected under the old lines with this number, who may be running elsewhere; the dossier above names who is running here.
The money
| Candidate | Raised | Cash on hand | PAC share | Self-funded | Outside $ for | Outside $ against |
|---|---|---|---|---|---|---|
| Platner, Graham (DEM) challenger · not on our roster | $21,050,419 | $1,763,058 | 1% | 0% | $426,355 | $9,230,161 |
| Collins, Susan M. (REP) incumbent | $16,169,827 | $11,038,115 | 7% | 0% | $2,437,057 | $1,335,724 |
| Mills, Janet Trafton (DEM) challenger · not on our roster | $6,063,106 | $102,783 | 2% | 0% | $17,900 | $0 |
| Wood, Jordan (DEM) challenger · not on our roster | $6,044,820 | $197,675 | 1% | 7% | $0 | $0 |
| Kleban, Dan (DEM) challenger · not on our roster | $458,786 | $86 | 0% | 47% | $0 | $0 |
| Bellows, Shenna (DEM) challenger · not on our roster | $381,371 | $136 | 0% | 0% | $0 | $0 |
| Rodriguez, Daira (DEM) challenger · not on our roster | $242,582 | $0 | 0% | 88% | $0 | $0 |
| Costello, David (DEM) challenger · not on our roster | $154,377 | $0 | 0% | 75% | $0 | $0 |
| Loud, Paige (DEM) challenger · not on our roster | $60,562 | $4,756 | 6% | 52% | $0 | $0 |
| Rench, Phillip (IND) challenger · not on our roster | $55,500 | $8,048 | 0% | 90% | $0 | $0 |
| Calabrese, Carmem Vincent Mr. (REP) challenger · not on our roster | $17,760 | $-3,500 | 0% | 0% | $0 | $0 |
| Calabrese, Carmen Vincent Mr. (REP) challenger · not on our roster | $17,760 | $-3,500 | 0% | 0% | $0 | $0 |
| Laflamme, Andrea (DEM) challenger · not on our roster | $16,254 | $10,043 | 0% | 11% | $0 | $0 |
| Favreau, Tucker (DEM) challenger · not on our roster | $13,599 | $7 | 0% | 64% | $0 | $0 |
| Evans, David Alan (IND) challenger · not on our roster | $6,437 | $0 | 0% | 0% | $0 | $0 |
FEC bulk candidate summaries through August 31, 2026; $13,447,197 of independent expenditures for or against these candidates this cycle (FEC Schedule E, types 24E and 24A), which is the parties' and outside groups' own revealed view of whether this seat is in play.
How it has voted for president
| Two-party margin | 2016 | 2020 | 2024 |
|---|---|---|---|
| President | D+2.9 | D+8.9 | D+6.6 |
A shift of 3.7 points toward the Democrats from 2016 to 2024. county returns summed; MEDSL county file (2016), an MIT-licensed county file (2020, checked against certified state results) and MEDSL precinct returns (2024). For a district split across counties this is an estimate, and where the state published the exact 2024 figure for these lines, that exact figure is the one the model uses.
The state in numbers
| Measure | State | Average state | Difference |
|---|---|---|---|
| Bachelor's degree or higher, 25+, 2023 | 35.3% | 34.0% | +1.3 pts |
| White, non-Hispanic, 2023 | 90.6% | 66.3% | +24.4 pts |
| Black, non-Hispanic, 2023 | 1.6% | 10.1% | -8.5 pts |
| Hispanic or Latino, 2023 | 2.1% | 12.9% | -10.8 pts |
| Asian, non-Hispanic, 2023 | 1.1% | 4.4% | -3.3 pts |
| Foreign-born, 2023 | 3.9% | 9.6% | -5.7 pts |
| Median age, 2023 | 44.8 | 39.1 | +5.72 |
| Median household income, 2023 | $71,773 | $77,633 | $-5,860 |
| Median home value, 2023 | $266,400 | $314,132 | $-47,732 |
| Owner-occupied homes, 2023 | 74.0% | 67.4% | +6.7 pts |
| Unemployment (ACS), 2023 | 3.9% | 4.8% | -0.9 pts |
| Federal government workers, 2023 | 2.5% | 3.0% | -0.5 pts |
| Work from home, 2023 | 14.1% | 12.3% | +1.9 pts |
| Households on SNAP, 2023 | 11.8% | 11.1% | +0.7 pts |
| Households with Social Security income, 2023 | 37.3% | 32.1% | +5.2 pts |
| Households with public assistance income, 2023 | 2.8% | 2.6% | +0.1 pts |
| Moved in from another state, past year, 2023 | 2.8% | 2.9% | -0.1 pts |
| Gini index, 2023 | 0.46 | 0.47 | -0.01 |
| Unemployment, latest month (BLS), 2026-07 | 3.0% | 4.0% | -1.0 pts |
| Change in unemployment, past 12 months, 2026-07 | -0.0 pts | -0.1 pts | +0.1 pts |
| Change since the last election (24 months), 2026-07 | +0.2 pts | -0.1 pts | +0.3 pts |
| Per-capita personal income (BEA), 2024 | $68,932 | $70,662 | $-1,730 |
| Per-capita income growth since 2019, nominal, 2024 | 37.9% | 32.4% | +5.5 pts |
| Government and other transfers, share of income, 2024 | 22.9% | 19.4% | +3.5 pts |
| Social Security, share of income, 2022 | 7.5% | 6.1% | +1.4 pts |
| Medicare, share of income, 2022 | 5.3% | 4.4% | +0.9 pts |
| Medicaid, share of income, 2022 | 4.6% | 3.8% | +0.8 pts |
| SNAP, share of income, 2022 | 0.6% | 0.6% | +0.1 pts |
| Earned Income Tax Credit, share of income, 2022 | 0.2% | 0.3% | -0.1 pts |
| Veterans' benefits, share of income, 2022 | 1.2% | 0.9% | +0.3 pts |
| Federal civilian jobs, share of all jobs, 2022 | 1.9% | 1.5% | +0.4 pts |
| Military jobs, share of all jobs, 2022 | 0.5% | 1.2% | -0.6 pts |
ACS 5-year state tables; BLS county unemployment and BEA county income, transfers and jobs summed to the state. Every figure is a named column of a named public-domain table, archived before it was read.
Who is ahead, and by how much?
Two numbers because they answer two questions. The nowcast is where opinion stands; the election-day forecast is where it is likely to end up.
How likely is each to win?
Monte Carlo error is ±0.2 points. A change smaller than that is simulation noise rather than news, and this page will not describe it as movement.
How wide is the range?
Nowcast: 90% of simulations fall between -8.6 and +9.3 points. Election day: -14.3 to +7.8. The election-day interval is 4.2 points wider, which is the 33 days of movement still to come.
What is the uncertainty made of?
Total sd 7.03 points, made of race-specific polling error 50%, drift to election day 33%, correlated polling error 12%, latent opinion 5%. The decomposition is stored with the forecast rather than reconstructed, so a probability whose dominant input is a placeholder is visibly that.
What evidence is this built on?
16 polls, most recent 2026-10-01. 25% verified against a primary source.
What changed since the last run?
Shaded band is the 90% interval, line is the central estimate, positive is Troy Jackson ahead of Susan Collins. Over 18 stored forecasts the central estimate moved -5.8 points. There were 7 specification changes (marked on the axis) and 2 new polls arrived over this window — so the movement mixes new evidence with changes to the model.
Since 2026-10-01: margin +0.00 points, win probability +0.0 points, on +0 polls. Of that, +0.00 points came from +0 poll(s), +0.00 from the shorter horizon, and -0.00 from the model specification.
How has this model done before?
Measured on 230 forecasts across 230 races in cycles 2016,2018,2020,2022,2024: mean absolute error 4.56 points, Brier score 0.0543. The nominal 90% interval contained the result 94% of the time, the 80% interval 84%, and the 50% interval 47%. Read that with care: a national polling miss moves every race in a cycle at once, so the sample size for a question about the intervals is 5 cycle(s), not 230 forecasts. Per cycle -- bias +1.644 pts; 2016: n=43 bias=+4.68 cov90=0.860; 2018: n=63 bias=-0.52 cov90=1.000; 2020: n=35 bias=+5.44 cov90=0.886; 2022: n=54 bias=-0.60 cov90=0.944; 2024: n=35 bias=+1.48 cov90=1.000.
Where did every number come from?
Nowcast run e95afe90-d49a-46af-a344-77a2f07eac86 and election-day run 28989b58-d23a-4251-bdcc-4c5246448eab, model single_race_latent/0.8.1 at commit bdf7e83107c17a2399efe61a44ef1bbee48f9284, seeds 20260924 and 20260924.