Maine Senate race odds: Troy Jackson vs Susan Collins on Polymarket and Kalshi
Democrat Troy Jackson, who replaced Graham Platner on the ballot in July, is about a 65% favourite against Senator Susan Collins in prediction markets. The odds, the October polls, what happened to Platner, ranked-choice voting and Collins’s 2020 comeback.
Prediction markets favour Democrat Troy Jackson to unseat Senator Susan Collins in Maine. Polymarket gives Jackson about 65.5% and Kalshi about 65%, with Collins at roughly 35%. The election is on 3 November 2026.
If you are searching for Graham Platner odds: Platner won the Democratic primary but withdrew in July, and Jackson replaced him as the nominee.
Prices as of 22 October 2026. Odds move daily; see the live markets below.
Maine Senate odds today
| Candidate | Polymarket | Kalshi |
|---|---|---|
| Troy Jackson (Democrat) | 65.5% | 65% (bid 64¢, ask 65¢) |
| Susan Collins (Republican) | 34.5% | 36% |
The price has moved fast: Kalshi had Jackson at about 57% on 16 October, so the market has added some 8 points in a week. Most of the recent rise in Democrats' Senate-control odds came from this one race. Live prices: Maine Senate on Polymarket · Maine Senate on Kalshi · our Maine Senate race page.
What happened to Graham Platner?
Platner, a Marine veteran and oyster farmer, won the Democratic primary in June. In early July he said he would leave the race after a sexual assault allegation, which he denies, and he formally withdrew on 10 July. Maine law let the state party choose a replacement: on 25 July, convention delegates nominated Troy Jackson, the former president of the Maine Senate, with 566 of 571 votes. Critics called the process rushed; supporters pointed to the deadline, 99 days before the election.
Polymarket markets that named Platner are settled by their own rules; the live market lists Jackson.
What the polls say
| Poll | When | Jackson | Collins |
|---|---|---|---|
| Suffolk University | Released 14 October | 47% | 49% |
| AARP | Published 1 October | 50% | 47% |
Marist and Washington Post/George Mason polls in October also had Jackson ahead, by about 4 points. A Pollsmax average of 24 polls had Jackson ahead 49.2% to 46.6%. The Cook Political Report rates the race a Toss Up.
Why the market is not more confident
Collins has beaten the polls before. In 2020 almost every public poll had Democrat Sara Gideon ahead, and Collins won by about 9 points. Traders who remember that are the reason Jackson trades near 65% rather than 75% despite leading most polls.
Ranked-choice voting. Maine uses ranked-choice voting for federal general elections. If no candidate wins a majority of first choices, the last-placed candidates are eliminated and their voters' next choices are counted. In a close race with minor candidates, that can decide the result after election night, and markets resolve on the certified winner (how markets resolve).
Why Maine matters for the Senate
Maine is one of the five Republican-held seats where markets favour the Democrat. Democrats need a net gain of four seats to control the Senate; the others in play are North Carolina, Ohio, Alaska and Texas (Texas Senate odds). The full map is in our Senate and House control odds.
Maine Senate odds: frequently asked questions
Who is favoured in the Maine Senate race?
Troy Jackson, at about 65% on Polymarket and Kalshi as of 22 October 2026.
Is Graham Platner still running?
No. He withdrew on 10 July 2026; Troy Jackson was nominated on 25 July.
What do the polls say?
Most October polls have Jackson ahead by 3–4 points; Suffolk had Collins up 2.
Does Maine use ranked-choice voting for Senate?
Yes, for federal general elections.
How long has Susan Collins been a senator?
Since 1997; she is seeking a sixth term.
