Primary
Democratic Primary
Held June 9, 2026.
| Candidate | Votes | % | |
|---|---|---|---|
| Graham Platner ✓ — Withdrew | 154,084 | 72.1% | |
| Janet Mills | 41,644 | 19.2% | |
| David Costello | 17,560 | 8.1% | |
| Andrea LaFlamme | 1,114 | 0.5% |
Republican Primary
Held June 9, 2026.
| Candidate | Votes | % | |
|---|---|---|---|
| Susan Collins ✓ | 126,398 | 100.0% |
Full calendar and every race: Maine primary guide
Race Overview
General Election Polling Trend
PollingSource average — trailing average of all polls from the last 30 days.
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Candidates
Susan Collins Nominee Incumbent
Republican
Troy Jackson Nominee
DemocratChosen as the Democrat nominee at the July 25, 2026 state convention in Bangor after Graham Platner withdrew; faces Sen. Susan Collins in November.
Graham Platner Won Primary — Withdrew
DemocratGraham Platner won the June 9 Democratic primary with 72.1% but withdrew from the race in July 2026. Maine Democrats nominated Troy Jackson at the July 25, 2026 state convention in Bangor.
General Election Polling Average
Average reflects all polls from the last 30 days; table shows the most recent 30 days or the newest 3 polls, whichever is more — subscribe for the full history. How accurate is each pollster? →
| Pollster | Date | Sample | MoE | Dem | Rep |
|---|---|---|---|---|---|
| InsiderAdvantage ±1.9 | 2026-09-23 | 1200 LV | ±2.83 | Jackson 46.00% | Collins 46.00% |
| Siena College Research Institute | 2026-09-22 | 619 LV | ±4.90 | Troy Jackson 46.00% | Susan Collins 49.00% |
| New York Times/Siena University ±3.1 | 2026-09-22 | 619 LV | ±4.90 | Troy Jackson 46.00% | Susan Collins 49.00% |
| New York Times/Siena | 2026-09-22 | 619 LV | Troy Jackson 46.00% | Susan Collins 49.00% | |
| University of New Hampshire | 2026-09-21 | 1312 LV | ±2.70 | Troy Jackson 51.00% | Susan Collins 47.00% |
| Quantus Insights (R) partisan·R | 2026-09-15 | 621 LV | ±4.30 | Troy Jackson 47.00% | Susan Collins 48.00% |
| University of Massachusetts/YouGov | 2026-09-14 | 650 LV | ±4.70 | Troy Jackson 48.00% | Susan Collins 43.00% |
| Rasmussen Reports (R) ±2.1 | 2026-09-10 | 1033 LV | ±3.00 | Troy Jackson 46.00% | Susan Collins 45.00% |
| YouGov | 2026-09-08 | 1335 LV | ±4.90 | Troy Jackson 48.00% | Susan Collins 44.00% |
| SSRS | 2026-09-06 | 880 LV | ±3.70 | Troy Jackson 48.00% | Susan Collins 45.00% |
Questions About This Race
Who is winning the 2026 Maine Senate race?
Troy Jackson leads Susan Collins 47.5% to 45.9% in the PollingSource polling average — a D+1.6 margin based on 8 polls from the last 30 days.
Is the 2026 Maine Senate race competitive?
Yes — the PollingSource polling average rates this race a Toss-up, the most competitive category.
What does the latest poll of the 2026 Maine Senate race say?
The most recent public poll, from InsiderAdvantage (completed September 23, 2026), found Jackson (D) at 46% and Collins (R) at 46%.
When is the 2026 Maine Senate race decided?
Election Day is Tuesday, November 3, 2026.
How is the PollingSource average calculated?
The PollingSource average is the unweighted mean of every scientific public poll of the race from the last 30 days — we do not exclude pollsters. Each race page lists the individual polls behind the average with pollster, field dates, sample size, and margin of error. Full details: pollingsource.com/methodology.
Race Notes
Graham Platner won the June 9 Democratic primary with 72.1% but withdrew from the race in July 2026. Maine Democrats nominated Troy Jackson at the July 25, 2026 state convention in Bangor.
Independent Expenditures Updated 3 hours ago
Top Spenders
- WINSENATE Dem-aligned $11,013,539
- PINE TREE RESULTS PAC GOP-aligned $9,293,145
- GOVERNMENT THAT WORKS PAC Dem-aligned $3,723,322
- SLF PAC GOP-aligned $2,671,485
- THE MAINE STANDARD GOP-aligned $2,299,737
- LEAD MAINE COMMITTEE, INC. GOP-aligned $1,322,959
- STRONGER MAINE GOP-aligned $1,187,225
- END CITIZENS UNITED ACTION FUND Dem-aligned $1,000,000
- AMERICA PAC GOP-aligned $756,796
- PLANNED PARENTHOOD VOTES Dem-aligned $750,000
Full outside-spending research — every committee, every race →