OLD TOWN, Maine — Shortly after Barack Obama won and Susan Collins was reelected in 2008, the president invited her to the White House to pitch the economic stimulus. It was not particularly subtle.

“He said: ‘You know Susan, they really like me in Maine. And I did really well in the last election,’” Collins recounted over sandwiches at the Governor’s Restaurant in Eastern Maine. “I practically had to bite my tongue in two to avoid saying: ‘They do like you Mr. President, but they liked me better.’”

For Collins to win a fifth term, she needs Mainers to again like her more than the current White House occupant. A whole lot more.

The 66-year-old political giant is facing the race of her life despite her universal name recognition and bipartisan reputation. President Donald Trump is targeting Maine as a battleground while his divisive politics has cleaved the state in two, and Collins has to share the ticket with him.

National Democrats, meanwhile, are backing Sara Gideon as her likely opponent, a battle-tested statehouse speaker who raised more than $1 million in the week after her launch.

Projected to be the most expensive in Maine’s history, the race is of imperative importance for party leaders and the Senate institution itself. With scarce opportunities elsewhere, Senate Democrats essentially need Gideon to win to gain a minimum of three seats and the majority. In the Senate, a Collins loss would be a potentially fatal blow to the reeling center of the chamber.

Faced with a cavalcade of challenges, Collins is projecting confidence while balancing her meticulous senatorial approach with an unmistakable shift into campaign mode. Collins, who is sitting on $5 million in campaign cash, bashes Gideon as a candidate who has “outsourced her campaign” to Washington and her longtime aides are gearing up for a knife fight.

Collins’ approval ratings, though, dipped below 50 percent in one poll. Republican strategists say they have her above 50 percent but acknowledge her unfavorables are up.

Collins is self-aware of her plight. She knows supporting Supreme Court Justice Brett Kavanaugh cost her and laments that decision helped bring the permanent campaign to Vacationland.

“Have I lost some votes because of my decision to support Justice Kavanaugh? Yes, I have. And I’m sad about that because I explained in great depth my decision-making,” Collins said. But “there still is an appreciation in Maine for someone who looks at the facts of an issue, votes with integrity and independence.”

Party leaders are openly preoccupied with Collins’ fate.

“We’re paying a lot of attention to it. She’s made some tough votes, she stepped up big time and did a very courageous thing ... on the Kavanaugh vote. But there’s a political price that comes with that,” acknowledged Senate Majority Whip John Thune (R-S.D.). “She’s the person that can keep that seat.”

Collins hasn’t officially announced her campaign, though it would take a seismic event for her not to run.

“No doubt that this is going to be a tough race,” Collins said. But “those who are eager to count me out … should take a look at [2008], where I had a truly, very worthy superior candidate.”

That’s a swipe at Gideon, an energetic 47-year-old mother of three who is eager to contrast Collins’ efficacy in the Trump era with her own role battling former Gov. Paul LePage and pushing progressive legislation. The race is already getting ugly.

Gideon says Mainers are “worried” that special interests are coming before them and suggests Collins stood by while thousands lost their lives to gun violence. Collins and her team see Gideon as a hypocrite on big money in politics and are ready to whack her for corporate donations and a campaign finance violation.

The tense atmosphere is not what Maine, or Collins, is used to. The Trump Era has frustrated a senator known for rigorous research, mild manners and a belief the Senate can still solve problems.

She toils away on health care legislation, then is confronted with the president’s tweets. She voted against the Obamacare repeal, then the administration backed a lawsuit aimed at sweeping the health law away.

Collins herself has no real relationship with the president, though she speaks with his daughter Ivanka Trump on topics like family leave and apprenticeships. More than anything, Collins resents the notion that she hasn’t stood up to the president.

“It’s never enough. Never. For those who truly hate the president, I’m never going to be able to do enough for them,” Collins said between bites of banh mi, which she frugally tucks into a to-go container before hurrying to a paper mill reopening. “I get tired of the ‘she speaks but doesn’t act.’”

Collins supported Trump’s Supreme Court nominees, but voted against Betsy DeVos as Education secretary and tried to override many of Trump’s vetoes. She took the lead on disapproving of Trump’s emergency declaration at the border.

Senate Democrats like working with Collins but would much rather have the majority. And to some, she’s in the way.

“This isn’t about Susan,” said Sen. Chris Murphy (D-Conn.). “You’ve got to make winning back the Senate a priority.”

Unlike most Senate races in 2020, Collins’s bid is a true referendum on her. Maine is not transient and everyone knows her.

Collins, one of two true GOP moderates along with Alaska Sen. Lisa Murkowski, is hyperfocused on Maine issues as the chairwoman of the Senate’s Special Committee on Aging (demographically, Maine is the oldest state) and is often a lonely, if reserved, critic of Trump.

Collins’ strategy appeals to the middle. But Trump's polarity gives Gideon an opening.

“She has voted with her party more than she ever has before. And I think that is worth repeating and remembering,” Gideon said over coffee in left-leaning Portland. “Part of the whole aspect of Mainers feeling left behind by Sen. Collins is she can not decisively say where she is on an issue.”

Gideon asserts that Collins is no longer the senator she once was, after her support for Trump’s nominees, the tax cuts that endangered Obamacare and her lack of a firm stance on Trump’s reelection. No matter how you ask about Trump’s 2020 campaign, Collins answers the same: “Not going to go there.”

“There will come a time when she’s going to have to make decisions and really tell people where she stands,” Gideon said.

Yet Gideon isn’t firm on hot-button issues herself. Eager to avoid the GOP’s “socialist” label, she won’t explicitly endorse Medicare for All or the Green New Deal but says climate change and universal health care access are priorities.

She doesn’t say whether she would support Senate Minority Leader Chuck Schumer as leader and doesn’t have a “fully developed position” on expanding or reforming the Supreme Court.

“You’re asking me questions that my six-week-old campaign self has not quite gotten to yet,” Gideon said, when asked about the legislative filibuster, which Collins defends.

The Democratic Senatorial Campaign Committee endorsed Gideon shortly after she launched her campaign, snubbing liberal candidate Betsy Sweet. Backed by the progressive Justice Democrats, Sweet says Gideon’s strategy is misguided.

“Careful, try not to say too much, don’t ruffle any feathers,” Sweet said of Gideon. “People are hungry for real policy and they’re hungry for real ideas.”

But national Democrats argue Gideon has put the race on the map as much as Trump, with DSCC Chairwoman Catherine Cortez Masto (D-Nev.) calling her “a tremendous candidate.”

It will take more than that to beat Collins, who has always been able to balance the divergent needs in the “Two Maines,” split between a pair of congressional districts drifting in opposite directions.

Prosperous Southern Maine has tourists, Portland’s booming restaurant scene and big-city transplants. The feeling there: Collins is toast.

The rest of the state largely resides in the sprawling Second Congressional District. This is Trump Country with shuttered paper mills, endless forests and economic challenges. It’s also the heart of Collins’s support.

At the Governor’s Restaurant, she’s stopped repeatedly by fawning diners. These voters are decidedly not on Twitter fuming about their senator. But they’ll feel the effects of the resistance against Collins soon enough.

Advertising Analytics projects spending in the race at $55 million, easily the most expensive in Maine history. Outside groups are already softening up Collins.

“People in Maine do not like billionaires coming to our state to take out our senator,” said former GOP state Sen. David Trahan.

Collins adds: “I have never seen the far left as energized."

The left is only one piece of Maine’s intricate political puzzle, a state that never neatly breaks down party lines. A prime example: moderate Democratic Rep. Jared Golden, a former Collins staffer, will stay neutral in the race.

“I haven’t met anyone who works harder than her to be honest with you. And obviously I’m working hard to try to follow in her footsteps,” he said of Collins.

Sen. Angus King (I-Maine), who endorsed Collins in 2014, won’t say whether he will do so again. Sen. Joe Manchin (D-W.Va.) endorsed Collins, earning himself an angry call from Schumer.

“I can’t believe everyone’s so damn hypocritical. She’s the one person I work with all the time,” Manchin said. “Why would you not expect me to do that?”

“Yes,” said Sen. Dianne Feinstein (D-Calif.), when asked if she’s conflicted. “I’m very fond of her. I consider her a friend. I trust her. I believe she’s a good senator.”

For others, winning the majority is far more important than playing nice in the Senate’s shrinking center. Collins said she supports Mitch McConnell as GOP leader, which is all some colleagues need to hear.

“Any vote to put Mitch McConnell in the leader’s chair is a vote to stifle climate action, period, end of story. It’s pretty categorical,” said Sen. Sheldon Whitehouse (D-R.I.).

Collins says some of the people rooting for her defeat are the same ones on the Senate floor each day, eager to speak with her.

“I have literally a line of people waiting to talk to me about: ‘Could you co-sponsor this bill, could you sign this letter?’” she said. “Clearly, my support is valued.”

In 2020, Trump will likely win an electoral vote in Maine’s Second District but lose the state overall. That means Collins probably needs thousands of voters to split their tickets. And the dynamics are anything but fixed.

Republicans harbor long-shot hopes that the Democratic primary gets ugly, aiming to elevate Sweet and put Gideon at odds with liberals. And Collins faces a potential time bomb with the Obamacare lawsuit, which originated from the GOP’s tax bill that killed the law’s individual mandate. She’s confident Kavanaugh will not strike down the entire law, which could fundamentally alter the race.

Rep. Tom Allen (D-Maine), whom Collins handily dispatched in 2008, admitted she maintains an edge despite the massive national campaign against her. But he drew a parallel to another famous Maine Republican senator, not entirely favorable.

“Someone that’s elected four times to the U.S. Senate has got to be a favorite,” he said. But Margaret Chase Smith “ran for a fifth term. And she got beat. Susan Collins is running for a fifth term. And I think the chances of her being beaten are pretty good.”