PORTLAND, Maine (AP) — When Republican Sen. Susan Collins had to vote on a Supreme Court justice in 2018, she deliberated under the spotlight for weeks, building suspense that ended with a dramatic floor speech. When she announced her support for President Donald Trump’s nominee, she triggered an onslaught of Democratic anger.

On Monday, Collins cast her vote against Trump’s pick without any speech and quickly headed home to Maine to try to save her political career.

Collins' contrasting moves on the Supreme Court nominations of Brett Kavanaugh and Amy Coney Barrett underscore the difficulty for a senator trying to find middle ground in an election in which the battle lines appear starker than ever. Her vote in favor of Kavanaugh rallied Democrats against her and angered some moderate supporters, while her vote against Barrett may not do much to win them back.

Throughout the campaign, the four-term senator has had to fight off accusations that her years in Washington have changed her and that she puts Trump, Senate Majority Leader Mitch McConnell and the GOP over the interests of regular Mainers.

“I was taught to give back to my community, to serve others and to act with integrity. That’s what I’ve always done,” Collins told The Associated Press. “I certainly have not changed.”

But Maine and American politics are changing.

The state known for its fierce independent spirit as much as its lighthouses and lobsters is becoming less so, and Democrats, not independents, now comprise the biggest voting bloc.

Throw in a well-funded opponent, along with a polarizing president, and the last Republican member of Congress from New England finds herself battling for her political survival.

Collins' Democratic rival, Sara Gideon, the speaker of the Maine House, called the senator's vote against Barrett “nothing more than a political calculation.”

Collins' spokesperson fired back by accusing Gideon of making “a craven political calculation seven months ago when she shut down the Legislature to focus on her campaign.”

Polls show an extremely close race despite more than $120 million allocated for ads by the candidates and their allies. And the money is still pouring into the race, one of a handful that could decide which party controls the Senate.

Losing the fundraising battle, Collins is focusing on her message that she's an experienced, bipartisan senator who’s in line to become chair of the appropriations committee, which directs all federal spending. That would be in stark contrast, she said, to a “rookie” senator.

Gideon is using the latest battle over a Supreme Court nominee to remind voters that Collins backed most of Trump's judicial nominees, resulting in a rightward shift in the judiciary. She's also attacking Collins’ vote for Trump's tax cuts that she says favored the rich over working-class Mainers.

Gideon said for all of Collins' talk about seniority, she doesn’t have much influence in her caucus, as demonstrated in her inability to stop the vote on Barrett. Collins, who has never missed a vote, said she voted against Barrett out of fairness to Democrats, who were denied an election-year vote on then-President Barack Obama’s nominee in 2016.

“It doesn’t seem like her seniority has much influence in her caucus, or that ability to bring things home for Mainers,” Gideon said.

Collins easily won her last election, and it was just a couple of years ago that the senator was cheered when Cyndi Lauper welcomed her onstage during a concert on the Bangor riverfront, a year before the Kavanaugh vote galvanized Democrats.

“This woman is a hero. And she’s my hero. And she’s a Republican,” Lauper told the crowd as she walked Collins to the center of the stage. Lauper praised her for her work with LGBTQ homeless youth.

But things have changed since then. The Human Rights Campaign, which had endorsed Collins in three previous elections, now endorses Gideon. The Planned Parenthood Action Fund, which was neutral in Collins’ 2014 race, is backing Gideon.

Collins, 67, insists she’s the same centrist who’s willing to work with members of either party. She also points to the millions she's brought home for Maine, including Bath Iron Works and Portsmouth Naval Shipyard, and her Paycheck Protection Program that helped more than 250,000 Mainers during the coronavirus pandemic.

“Susan Collins is exactly the same person she was when she was first elected. Certainly, the national discourse has changed tremendously,” said Kevin Raye, former chief of staff for retired Republican Sen. Olympia Snowe.

On the campaign trail, Gideon, 48, is known for her socially distanced “Supper with Sara” events held under a tent.

Collins, meanwhile, has been on a bus tour across the state.

Jeff Corey, president of Days Jewelers, met Collins during a visit to Waterville and said Collins’ experience, pragmatism and bipartisanship make her the best candidate to serve the interests of Mainers.

“Look, the American people right now are looking for collaboration with our leaders, finding common ground and getting things done,” he said, noting that the Lugar Center at Georgetown University has ranked Collins as the most bipartisan senator.

Among Democrats, Collins doesn’t get much credit for standing up to Trump, even though she has been critical of his handling of the pandemic, his attempt to strike down the Affordable Care Act, the diversion of funding for the border wall and the removal of protesters from Lafayette Square for a photo op.

Critics say she hasn’t been forceful enough in her denunciations of Trump. Collins has declined to say whom she’ll vote for on Election Day. She wrote in a candidate in 2016 rather than vote for Trump.

James Bennett, a former Republican who’s supporting Gideon, said it’s time for a change. “I’d thought of her as being an independent thinker until the last four years. She’s not thinking for herself. She’s just following the party line,” said Bennett, a retired defense contractor from Camden.

The race will be decided by ranked choice voting, providing a new layer of uncertainty. Under the election system, voters will get to rank all four candidates — including two independents, progressive Lisa Savage and conservative Max Linn — in order of preference. If no one wins a majority of first-place votes, then the last-place candidates are eliminated and those voters’ second choices are reallocated until a majority winner emerges.

Collins is trying to avoid the same fate as her mentor, the late Sen. Margaret Chase Smith. Smith was the first woman to serve in both chambers of Congress, and she made a name for herself with her “Declaration of Conscience” speech decrying McCarthyism in 1950.

Smith was a formidable politician, but she was ousted from the Senate in 1972 amid accusations that she was out of touch.

Unlike Smith, Collins has raised money, kept a strong organization in the state and campaigned hard.

But the patch of middle ground occupied by moderates has become smaller and smaller, said Jack Pitney, a political science professor at Claremont McKenna College in California.

“She sticks to the middle of the road. Unfortunately, the middle of the road is filled with roadkill,” he said.