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Who will win the 2026 Maine Senate Democratic Primary?

Jun 10, 2026, 3:59am UTC, 45 days agoLast updated: Jun 9, 2026, 10:23 PM UTC

Maine Democratic Senate nominee?

$6.1M

JUN 10, 2026

Primary Election

Party selects its nominee.

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OddsCurrent Odds

Track how candidate odds have moved across common market windows.

Total volume

$6.1M

24h volume

$237.9K

G. Platner100%

D. Costello1%

A. LaFlamme1%

No chart data available yet.

source: Kalshi

Upcoming Events

November

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Maine 2026 general election

News

AINews Summary

Troy Jackson has effectively locked up support for the Maine Democratic Senate nomination after Graham Platner withdrew from the race. Democrats will formally pick their replacement nominee at a July 25 convention in Bangor, but Jackson now looks like the clear frontrunner. Jackson’s odds appear to have strengthened sharply, but the nomination is still not official. The market should now price in less uncertainty around the Democratic nominee, though the convention could still matter.

Articles

WWJLA7 hours ago

Troy Jackson replaces Graham Platner as Maine Democrats' US Senate nominee

Former Maine Senate President Troy Jackson secured the Democratic nomination for the U.S. Senate on Saturday.

TAThe Atlanta Journal-Constitution7 hours ago

Maine Democratic delegates choose Troy Jackson as new nominee to face US Sen. Susan Collins

Former state lawmaker and logger Troy Jackson has secured the Democratic nomination for U.S. Senate in Maine on Saturday. He will face longtime GOP Sen. Susan Collins in November in a race that could decide which party controls the Senate. Jackson replaces Graham Platner, who won the Democratic primary in June but withdrew from the race earlier this month following an allegation of sexual assault that Platner has denied. Platner’s exit forced Democrats to quickly come up with a never-before-used process to choose a new nominee, which involved hundreds of delegates from across the state gathering in Bangor, about 130 miles (209 kilometers) north of Portland, to vote on a new nominee. Jackson won the support of almost all delegates to clinch the nomination.

UTUSA TODAY8 hours ago

Troy Jackson replaces Graham Platner as Maine Senate Democrat nominee

Jackson will face incumbent Sen. Susan Collins, R-Maine, in the race that could determine the balance of power in the U.S. Senate.

WEWashington Examiner13 hours ago

Democratic establishment fights back against socialists

Democratic leaders are circling the wagons around Rep. Haley Stevens (D-MI) against her left-wing opponent, Abdul el Sayed.

BNBreitbart News Network2 days ago

'Let’s Just Say That We Have a Candidate'

Democrats appear to be unsure of their potential replacement for scandal-plagued Graham Platner in Maine will work out in their favor.

REReading Eagle1 day ago

What to know on Troy Jackson, Maine Democrats' likely Senate nominee

Maine Democrats scrambling to replace Graham Platner for the Senate race against Susan Collins are expected to nominate Troy Jackson.

BNBaltimore News1 day ago

Fact Check Team: Why Maine Democrats are choosing a Senate nominee at a party convention

Maine Democrats are set to gather on Saturday for an unusual political event that could have national consequences.

Polls

Polling Average

80%60%40%20%0%

58.9%

29.8%

G. Platner

J. Mills

D. Costello

A. LaFlamme

Date (Start - End)	Spread	Platner	Mills	Costello	LaFlamme
Polling Average	Platner+29.1	58.9%	29.8%	2.1%	1.6%
Tavern ResearchJun 5 - 5	Platner+52.0	68.0%	16.0%	5.0%	2.0%
Tavern ResearchJun 5 - 5	Platner+38.0	69.0%	31.0%	–	–
University of New Hampshire Survey CenterMay 21 - 25	Platner+66.0	76.0%	10.0%	3.0%	–
Workbench StrategyApr 6 - 9	Platner+35.0	64.0%	29.0%	–	–
Maine People's Resource CenterMar 20 - 31	Platner+33.1	61.1%	28.0%	1.8%	–
Emerson CollegeMar 21 - 23	Platner+26.7	54.7%	28.0%	0.8%	1.6%
Impact ResearchMar 19 - 23	Platner+38.0	66.0%	28.0%	–	–
Quantus InsightsMar 3 - 5	Platner+5.3	43.3%	38.0%	–	–
Pan Atlantic ResearchFeb 13 - Mar 2	Platner+7.0	46.0%	39.0%	4.0%	–
University of New Hampshire Survey CenterFeb 12 - 16	Platner+38.0	64.0%	26.0%	1.0%	2.0%
Pan Atlantic ResearchNov 29 - Dec 7	Mills+10.0	37.0%	47.0%	1.0%	–
Z to A ResearchNov 14 - 18	Platner+20.0	58.0%	38.0%	0.0%	1.0%

Aggregation source: FiftyPlusOne

Endorsements

David Allen Costello

Gov. Janet Mills

Gov. Janet Mills endorsed David Costello in Maine's U.S. Senate race.

Who will win the 2026 Maine Senate Democratic Primary?

Maine Democratic Senate nominee?

OddsCurrent Odds

Upcoming Events

News

Troy Jackson replaces Graham Platner as Maine Democrats' US Senate nominee

Maine Democratic delegates choose Troy Jackson as new nominee to face US Sen. Susan Collins

Troy Jackson replaces Graham Platner as Maine Senate Democrat nominee

Democratic establishment fights back against socialists

'Let’s Just Say That We Have a Candidate'

What to know on Troy Jackson, Maine Democrats' likely Senate nominee

Fact Check Team: Why Maine Democrats are choosing a Senate nominee at a party convention

Polls

Endorsements

Fundraising

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Upcoming Events

News

Troy Jackson replaces Graham Platner as Maine Democrats' US Senate nominee

Maine Democratic delegates choose Troy Jackson as new nominee to face US Sen. Susan Collins

Troy Jackson replaces Graham Platner as Maine Senate Democrat nominee

Democratic establishment fights back against socialists

'Let’s Just Say That We Have a Candidate'

What to know on Troy Jackson, Maine Democrats' likely Senate nominee

Fact Check Team: Why Maine Democrats are choosing a Senate nominee at a party convention

Polls

Endorsements

Fundraising

Related races

Maine Democratic Senate nominee on Jul 31, 2026?

Maine Senate winner?

Maine Senate winner? (Person)

Maine Governor winner?