Susan Collins

Immigration and border security has become the second-most important issue for Maine voters, overtaking health care and political division after a fatal shooting involving a federal immigration officer intensified debate across the state.

Eighteen percent of respondents to a Fox News poll released on Wednesday named immigration and border security as the state's most important issue, up from 14 percent in June. Inflation and high prices remained the leading concern, cited by roughly one-third of voters.

ICE Shooting Intensifies Maine Immigration Debate

The shift follows the fatal July 13 shooting of Joan Sebastian Guerrero during an Immigration and Customs Enforcement (ICE) operation in Biddeford.

Read More on News

The Department of Homeland Security (DHS) said an officer fired after Guerrero attempted to flee in a vehicle, and that the officer feared for public safety. The Maine Attorney General's Office is investigating the use of deadly force. The office of Senator Angus King, a Maine independent, said Guerrero was not the target of the warrant being served, while federal officials had not clarified whether he was connected to the wider operation.

The shooting prompted protests and sharpened a political divide in the state's closely watched Senate race.

Democrat Troy Jackson, the former president of the Maine Senate, has described ICE as "a rogue agency" and called for it to be dismantled. Republican Senator Susan Collins, meanwhile, has called for an investigation into the shooting but faced criticism over her vote earlier this year to approve $70 billion for immigration enforcement.

Maine Senate Race Remains a Toss-up

The Fox News poll put Jackson at 48 percent and Collins at 46 percent, with the difference inside the survey's margin of error, which was plus or minus 3 percentage points. The poll surveyed 1,000 registered voters from August 6 to 10.

Last month, Jackson replaced Graham Platner as the Democratic nominee after Platner withdrew amid an assault allegation. Collins, first elected in 1996, is seeking a sixth term.

Yet the poll suggests candidate sentiment, rather than any single policy issue, may ultimately shape the result.

Among Jackson supporters, 61 percent said they were voting mainly against Collins, while 36 percent said they were voting primarily for Jackson. By contrast, 71 percent of Collins supporters said they were voting for her.

It also points to a broader vulnerability for Collins: her relationship with President Donald Trump. Fifty-five percent of voters said they were very or extremely concerned that Collins voted with the president too often, compared with 43 percent who expressed the same level of concern that Jackson was too close to the democratic socialist movement.

The contrast was particularly pronounced among independents, who were 13 points more likely to be concerned about Collins' alignment with Trump than Jackson's ties to democratic socialism, suggesting that the incumbent's association with the president may be a greater electoral liability than Republicans' attempts to portray her challenger as too progressive.

Immigration may have changed what Maine voters are discussing. But the election could still turn on the question that has shadowed Collins for years: whether voters believe she has remained in Washington too long.

Why the Maine Senate Race Matters for Control of Congress

Democrats have little room for error in their attempt to regain the Senate. Republicans hold 53 seats, while Democrats have 45 plus two independents who caucus with them. That means Democrats need a net gain of four seats to reach 51, since a 50-50 Senate would leave Republican Vice President JD Vance able to cast tie-breaking votes.

That makes Republican-held Maine one of the Democratic Party's most important pickup opportunities. Twenty-two Republican-held seats are being contested in the 2026 cycle, compared with 13 held by Democrats, but relatively few are considered genuinely competitive. Major election forecasters currently place Maine in or close to toss-up territory, making it one of a small number of races capable of altering the balance of power.

For Republicans, holding the seat would protect their path to a Senate majority even if they lose elsewhere. For Democrats, defeating Collins would provide one of the four gains they require, provided they also defend their own vulnerable seats. Control of the chamber will determine which party runs Senate committees and whether Trump can continue securing the confirmation of federal judges, Cabinet officials and other senior nominees through the second half of his term. The Constitution gives the Senate responsibility for providing advice and consent on those appointments.

The race also presents a distinctive test of ticket-splitting. Collins is the only Republican senator seeking reelection in 2026 from a state Trump lost in 2024, yet she has repeatedly outperformed her party in Maine, including winning reelection in 2020 by almost 9 percentage points.