Maine voters could determine control of the Senate when they either reelect Republican Sen. Susan Collins to a record sixth term or replace her with Democrat Troy Jackson.

ROBERT YOON WASHINGTON — Maine voters could determine control of the Senate on Tuesday when they either reelect Republican Sen. Susan Collins to a record sixth term or replace her with Democrat Troy Jackson. Also on the ballot are open-seat races to replace term-limited Democratic Gov. Janet Mills and retiring Democratic Rep. Jared Golden.

Republicans hold a 53-47 Senate majority, and defeating Collins is a key stepping stone for Democrats to pick up the four additional seats they need to retake the chamber. Republicans also hold a slim House majority, and flipping Golden’s seat would help blunt possible Democratic gains elsewhere in what’s expected to be a difficult midterm environment for the GOP.

Collins, the only Senate Republican to represent a state that former Democratic Vice President Kamala Harris carried in 2024, has been considered one of the chamber’s most vulnerable GOP incumbents in all five of her reelection campaigns. The 51% of the vote she received in her 2020 reelection bid was her poorest showing since the 49% she received in her first successful run in 1996. But despite Maine’s blue streak in presidential elections, Collins’ Democratic opponents have never surpassed the 44% mark in her five previous races. If reelected, Collins would become the state’s longest serving U.S. senator in May 2027.

Jackson is a former logger and former Republican who went on to serve as president of the state Senate as a Democrat. After an unsuccessful run for the Democratic nomination for governor, he was chosen by delegates at a state convention in July to replace Graham Platner as the Democratic nominee to challenge Collins. Platner easily won the June primary but was dogged by controversies surrounding a tattoo he once had that was recognized as a Nazi symbol and a sexual assault allegation he has denied. He withdrew from the race in early July.

Despite Jackson’s late entry into race, he has far outraised Collins since July, putting him slightly ahead of Collins’ total haul for the entire cycle. Both candidates have also received significant support from outside groups, including more than $30 million in ad spending on behalf of Collins from the super PAC affiliated with Republican Senate Majority Leader John Thune. With outside spending factored in, pro-Collins forces have outspent pro-Jackson forces in advertising since Sept. 1, $65 million to $55 million, according to AdImpact.

In the 2nd Congressional District, Golden’s announcement in November that he would not seek a fifth term gives Republicans a key pickup opportunity. Trump won the district in 2024 along with its one electoral vote Maine is one of two states that allocates some of its presidential electoral votes by congressional district.

Democratic state Auditor Matt Dunlap will face former two-term Republican Gov. Paul LePage for the seat. LePage has slightly outraised Dunlap, although the Democrat has remained competitive.

In the race for governor, Democrat Hannah Pingree and Republican Bobby Charles are the major party nominees to succeed Mills. Pingree is a former state House Speaker and daughter of Democratic Rep. Chellie Pingree, who represents Maine’s 1st District. Charles is a former U.S. State Department official. Independent state Sen. Rick Bennett is also on the ballot. He previously served as state Senate president as a Republican.

The governor’s office in Maine frequently changes party hands. The state hasn’t elected consecutive governors from the same party in 74 years.

Maine uses a ranked choice voting system in general elections for federal office. General elections for governor and the state legislature do not use ranked choice voting. Under the system, voters rank the candidates in order of preference. If no candidate receives a majority of first-place votes, the last-place candidate is dropped, and votes cast for that candidate are reallocated among the rest of the field according to the preferences of the dropped candidate’s voters. This process repeats until one candidate emerges with a majority of votes.

Although the races for Senate and the 2nd Congressional District each have only two candidates listed on the ballot, both contests are subject to ranked choice voting because of declared write-in candidates.

Maine is divided into 16 counties, but elections are run by the state’s hundreds of cities and towns, a practice common in New England. Portland is by far Maine’s most populous city and forms the heart of the state’s Democratic base. The two congressional districts largely track with the state’s political demographics. The 1st Congressional District along the Southern Maine Coast is heavily Democratic, while the massive 2nd District to the north includes the bulk of the smaller, more rural areas where Trump performed best in 2024.

Here are some of the key facts about the election and data points the AP Decision Team will monitor as the votes are tallied: When do polls close? Polls close at 8 p.m. ET. What’s on the ballot?

The Associated Press will provide vote results and declare winners for Senate, House, governor, state Senate and state House. How many people voted in the last midterm election? About 677,000 votes were cast in the 2022 race for Maine governor. How much of the vote is cast early or by absentee ballot?

About 36% of the vote in the 2022 race for Maine governor was cast early in-person or by mail. Mail ballots may be processed before Election Day, but the tabulation may not begin until after polls have closed.

The latest advance vote totals for Maine can be found in the AP’s advance vote tracker When are early and absentee votes released?

The state’s most populous cities and towns vary in how and when they release vote results, but results from all vote types tend to be released together over the course of the night. How long does vote counting usually take?

In the 2024 general election, the AP first reported results at 8:44 p.m. ET, or 44 minutes after polls closed. About 50% of the total vote had been counted by 12:54 a.m. ET, and counting stopped for the night at 4:11 a.m. ET. By 3:13 p.m. ET the day after Election Day, about 90% of the vote had been counted. When will the AP declare a winner?

The AP does not make projections and will declare a winner only when it’s determined there is no scenario that would allow a trailing candidate to close the gap. If a race has not been called, the AP will continue to cover any newsworthy developments, such as candidate concessions or declarations of victory. In doing so, the AP will make clear that it has not yet declared a winner and explain why. How do recounts work?

Under a 2025 law, recounts in Maine are automatic if the vote is tied. A candidate for statewide or multicounty office may request and pay for a recount, although the charges are waived if the vote margin is not more than 1% of the total votes cast or not more than 1,000 votes, whichever is less. The AP may declare a winner in a race that is subject to a recount if it can determine the lead is too large for a recount or legal challenge to change the outcome.