A Suffolk University poll of 500 likely voters shows Democratic candidate Troy Jackson holding a two-point advantage over Republican incumbent Susan Collins in the Maine Senate race. Conducted between October 8 and October 11, the survey placed Jackson at 49 percent and Collins at 47 percent, a gap that falls within the poll's margin of error of plus or minus 4.4 percentage points.

Jackson, a former president of the Maine Senate, led the overall tally by two points. Among voters who identified as independent, the survey placed Collins ahead by a narrow margin — 47 percent against 44 percent.

Exit-poll figures from a news outlet placed Jackson's Democratic support at 94 percent against 5 percent, a spread that differed from the 2020 contest, in which Democratic candidate Sara Gideon drew 84 percent of Democratic voters compared to Collins's 13 percent. Along the South Coast, Jackson's vote share reached 57 percent against 39 percent for Collins, while returns from the Mid Coast placed him at 55 percent to 41 percent. In East Maine, the split ran 55 percent for Collins against 41 percent for Jackson, while across the rural Northern region the gap widened to 71 percent for Collins versus 25 percent for Jackson.

Voters who rated themselves highly likely to cast a ballot broke for Jackson by a three-point margin, 50 percent to 47 percent.

Polling and political analysts have placed the 2026 Senate contest in Maine among the handful of races expected to draw the closest margins across the midterm cycle. Republicans currently hold 53 of the Senate's 100 seats against 47 held by Democrats. Analysts have identified both Maine and North Carolina as states where Democrats could gain Senate seats currently held by Republicans.

A joint survey from the Washington Post and George Mason University, fielding 800 likely voters between September 30 and October 5, placed Jackson ahead by four percentage points — 50 percent against 46 percent — within a sampling margin of plus or minus 3.6 points. A Marist University poll of 1,505 registered voters conducted between October 1 and 4 recorded a four-point gap in Jackson's favour — 51 percent against 47 percent — within a margin of error of plus or minus 3.8 percentage points. A YouGov/CBS News poll of 1,136 likely voters, carried out from September 23 through October 1, placed the two candidates at exactly equal footing — 50 percent apiece — with a sampling margin of plus or minus 4.7 percentage points. According to the RealClearPolitics polling average tallied through Wednesday, Jackson held a margin of 1.3 percentage points over Collins.

A fourth debate between Collins and Jackson is scheduled for 7 p.m. on October 15, with The Portland Press Herald listed among the co-organising partners. A prior Tuesday session saw Collins and Jackson address questions of data centre development alongside foreign policy matters.

The two candidates expressed broad agreement on placing limits on data centre growth, with Collins noting that she and Jackson held positions on the matter that were closer together than one might expect. On the Iran policy question, Jackson contended that Collins had an opportunity through her chairmanship of the Appropriations Committee to withhold funding but chose not to act, adding that Trump had been seeking military engagement while Collins declined to exercise the leverage available to her. Collins cited her voting record on invoking the War Powers Act's 60-day withdrawal provision as the basis for her argument that Trump lacked a coherent strategy regarding Iran.

Jackson received an endorsement from former President Barack Obama during the past week. Senator Bernie Sanders made a campaign appearance alongside Jackson during a weekend visit to Maine. A possible trip to Maine by President Trump before the midterms has been raised publicly.

Collins stated at an earlier debate that a presidential visit was unlikely, noting that her office had received no communication from the White House and that her relationship with the president was not a close one, adding that she did not expect him to travel to Maine. Separately, Collins joined fellow senators in a bipartisan statement opposing the administration's plan to bring in Russian diesel, with the statement arguing that the move ran counter to legislation passed in 2022 barring Russian energy imports as a measure against financing the conflict in Ukraine.

A political action committee backing Collins, Defending Main Street, placed advertising in Portland, Oregon, rather than the intended Portland, Maine. In a statement to the broadcaster, the committee attributed the placement error to a third-party media vendor, adding that the advertisements were pulled and corrected as soon as the problem came to their attention.

In-person absentee voting across Maine ran from October 5 through October 29, according to the state's secretary of state office. By the October 2 cutoff, absentee ballot applications from residents had topped 70,000. Polling place hours run from either 6 a.m. or 10 a.m. through 8 p.m., with the earlier opening applying to towns above a set population threshold.