The Republican senator campaigning on her clashes with Trump

As the US midterm elections get closer, Donald Trump's polling numbers keep diving further underwater.

And Republican Senate candidates are becoming more vocal about their differences with the president.

Michigan's Mike Rogers, an early tariffs supporter, is now calling for an end to the Canada trade war.

New Hampshire's John Sununu, who initially praised Trump's decision to attack Iran, now criticises the plan as flawed.

And Ohio's Jon Husted, who has championed data centres for years, now says they should only be built where the locals want them.

But in Maine, Susan Collins can lay claim to a long history of disagreements with Trump.

The veteran Republican, a fixture of the Senate since Bill Clinton was president, even voted to convict Trump after he was impeached over the January 6 insurrection.

"I'm not exactly his favourite senator," she said during one recent debate.

"I vote very independently," she told another.

Talking up her differences with Trump is a central part of Collins's strategy to keep her seat. It could be the key to helping his Republican Party keep control of the Senate.

Republicans see the Maine Senate seat as one they cannot afford to lose.

The local polls are hairbreadth tight, but Trump is unpopular in Maine. About twice as many Mainers disapprove of his performance than approve, according to Civiqs' public opinion tracker.

So the question is: Has Collins done enough to convince Mainers she will stand up to Trump when it counts?

For Lee Umphrey, who had consistently voted for Collins up until this year, the answer is no.

"I've known her a long time, she's done a lot of good, and for organisations like ours she has been very reliable," said Umphrey, who runs a community development corporation in Bangor, where Collins lives.

"[But] this is really a referendum on President Trump's executive power and the abuses connected to that."

He listed examples including the Elon Musk-led slashing of government services, cuts to Medicaid health insurance under the "Big Beautiful Bill", tariffs on Canada, and the war in Iran.

To some extent, Collins split with Trump on all four examples listed by Umphrey.

She voiced opposition to some DOGE cuts, voted against the Big Beautiful Bill, criticised the Canada tariffs, and supported Democrat-led resolutions to end the war.

She points to wins like her successful efforts to boost rural health funding in the Big Beautiful Bill and to remove tariffs from some Canadian products, including rock salt used on Maine's icy roads in winter.

Her Democratic opponent, Troy Jackson, mocks what he sees as meek efforts for meagre concessions.

"She's like an arsonist who helped set the fire and then she wants credit for bringing a cup of water to put it out," he said in one recent debate.

Her critics argue she too often caves to pressure.

"I'm sure that she has done good things for the state of Maine and for the country, but of late, ever since Trump has been on the scene, she's mostly been complicit," said Mary Ann Larson, part of a group that holds weekly protests against Collins and Trump.

Like many in Maine, Larson has not forgotten Collins's role in appointing Supreme Court judges that overturned abortion rights, including her critical vote to confirm Trump-nominee Brett Kavanaugh's appointment in 2018.

"So many women felt betrayed by that," Larson said. "We're half the population and we basically were disenfranchised by that vote."

Collins has a history of outperforming the polls.

When she was last up for election six years ago, polls predicted she would lose. But she won by nine percentage points.

Democrats' hopes for her defeat were high again earlier this year, as candidate Graham Platner attracted a huge groundswell of grassroots support.

But he was forced out of the race in July after being accused of sexual assault (which he denies).

One of the biggest blows to Collins's campaign came in September, when ProPublica published an investigation into alleged bribery.

Jackson called it "corruption of the highest order" but Collins denied wrongdoing, and the allegations do not look to have significantly dented her re-election effort.

Some of Collins's enduring electoral success is attributed to her work on low-key local issues and dealings with constituents.

Some locals offer personal stories when asked for their views on the senator, like Bangor local Lisa Thomas, who said she had bumped into Collins several times at the shops.

"About four years ago we were talking about pot roasts, and she gave me her mother's recipe. I've used it ever since, and it's great," said Thomas.

"Each time I see her, I always come to shake her hand and say, 'I appreciate you, I appreciate what you stand for, for goodness and equality.'"

Thomas was collecting a Susan Collins lawn sign at a family day for conservatives at a Bangor church, co-sponsored by the Republican Party.

Handing out the signs was 19-year-old volunteer Sofia Pride, who described Collins as "easy to support whichever side of the political spectrum you're on".

"I've always looked up to her," she said, recalling how Collins used to phone into a public radio show Pride worked on when she was at high school.

But when asked about Trump, Pride said: "I'm going to pass on the question if that's OK. I think it's not about him right now. It's about having Senator Collins win this race, and he's chosen not to be involved in it, and I think that says a lot."

Some attendees said they would vote for Collins despite having reservations about Trump.

"When he ran in 2024, he promised us no new wars," said three-time Trump voter Michael Capeci.

"Then he made the decision to go to war in Iran for supposed nuclear weapons that I don't think even exist.

"But I strongly support Susan Collins because she's delivered a lot of good money to the state of Maine and she's done so much to keep businesses open and get economic development and federal funds into the state."

Collins's campaign has focused on promoting her as a fighter for local causes as much as it has promoted her fights with Trump.

And the Trump administration delivered a gift to boost those messages in the final days of the campaign.

Last week, Collins announced the White House had agreed to another reduction on tariffs on Canadian products, including those deemed crucial to Maine's famed blueberry and apple industries.

The move could indicate Trump and his team fear his unpopularity could finally spell the end of Collins's electoral luck.

"There's a growing resentment that while he's doing well and the stock market's happy and his rich friends are happy, people on the street are hurting," said Umphrey, the community development head.

"We're seeing this all the time with diesel fuel, regular gasoline, food costs, healthcare costs all going up.

"I think any goodwill that Senator Collins has built up because of her good work is going to fade away, because it's pretty severe."