Her year began with the inauguration of a Republican president she publicly opposed.

By summer, she stood hard against the party itself, a loyal, lifelong Republican adamant in her refusal to scuttle the Affordable Care Act and leave tens of thousands of Mainers without access to health care.

Then came fall and, after weeks of rampant speculation from Maine’s State House to Capitol Hill, her dramatic announcement that she would forgo a race for governor and instead stay in the U.S. Senate.

Now, as the year ends, she remains in the spotlight, her vote to pass a major tax cut rooted in a bargain many dismissed as a fool’s errand.

Praised and vilified on both sides of the political divide, jubilant amid the applause yet defiant in the face of negative headlines, Sen. Susan Collins dominated Maine’s news landscape like no other throughout one of the most tumultuous years in U.S. political history.

Because of that, she is the Maine Sunday Telegram’s inaugural Mainer of the Year.

“It has been extremely challenging,” Collins said during a recent interview in her Senate office in Washington, D.C., reflecting on a year that was still moving beneath her feet. “And it’s been very exciting in a lot of ways because I love my state, I love public policy, I like the fact that I can help influence events.”

Pausing for a moment, she added, “I would be less than truthful if I didn’t say that it’s also been very stressful.”

Collins is surrounded by members of the media on her way to a Dec. 12 vote. Because of her moderate stance on some issues and because she has cast a vote against some Republican-backed legislation this year, Collins is often surrounded by reporters when she travels from her office to the Capitol.

She began the year on crutches, her ankle broken in two places from a fall on ice late last year in Bangor. It provided a fitting metaphor as she navigated the new administration of Donald Trump, himself the product of a party fractured between establishment Republicans like Collins and upstarts like Steve Bannon, who saw Trump’s rise as an invitation to political upheaval.

To stand against the leader of her own party did not come naturally to Collins, the daughter of a northern Maine family with deep-red Republican roots who long has presented herself as a moderate in an increasingly polarized Senate.

Never in her two decades on Capitol Hill, however, had Collins encountered a Republican quite like Trump. In a pre-election op-ed for The Washington Post, she’d made her distaste clear, announcing she could not support a candidate whose “lack of self-restraint and … barrage of ill-informed comments would make an already perilous world even more so.”

Yet now, Trump occupies the White House. And from the start, as she tentatively worked with the administration when it seemed possible and kept an arm’s length when it didn’t, Collins walked a politically perilous path.

Her wholehearted support for then-Sen. Jeff Sessions, R-Alabama, a longtime friend, to become attorney general drew widespread condemnation from those who saw Sessions as a racist and one of Trump’s earliest enablers.

Collins and Sen. Angus King laugh while talking with Sen. Tom Carper of Delaware, left, while riding in a subway car while on their way to a vote.

At the same time, Collins opposed Trump nominees Betsy DeVos for education secretary (too inexperienced) and Scott Pruitt as head of the Environmental Protection Agency (too anti-EPA). Both were confirmed anyway.

A member of the Senate Judiciary Committee, Collins soon found herself immersed in the ongoing investigation of Russian meddling in the 2016 election. That, in turn, led to her support for the appointment of Special Counsel Robert Mueller – “Bob Mueller has sterling credentials & is above reproach,” she tweeted – after Trump fired FBI Director James Comey in May.

But of all the issues roiling the nation’s capital in this era of hyper-partisanship, the Republicans’ long-sought repeal of the Affordable Care Act, or Obamacare, would thrust Collins onto center stage like nothing before in her 20-year Senate career.

In the wee hours of July 29, with the fate of Obamacare squarely in the hands of the Republican-controlled Senate, Collins stood for a roll call and voted “no” on a “skinny repeal” bill that would have cost some 16 million Americans their health insurance.

Her vote – combined with those of fellow Sens. Lisa Murkowski, R-Alaska, and John McCain, R-Arizona – tipped the Senate majority and derailed the repeal. Collins’ decision so impressed Sen. Angus King that he called a press conference upon landing in Portland that morning to laud his Maine colleague’s “courage and commitment” to her constituents.

“She had to jump off first,” recalled King, noting the alphabetical order of the roll call, in an interview last month. “I’m pretty sure she knew where Lisa (Murkowski) was. I don’t know if anyone knew where McCain was. But she did it.”

And for that vote, which she attributed to the countless Mainers who had begged her to save Obamacare, Collins was richly rewarded.

Social media overflowed with praise for her steadfastness in the face of intense pressure from Republican leaders. Upon her arrival that Friday at Bangor International Airport, the entire waiting area greeted her with an impromptu standing ovation.

“It was absolutely extraordinary,” Collins, clearly touched, said hours later. “It was just so affirming of what happens when you do the right thing.”

Collins, seated at right, listens to testimony during a hearing about prescription drug prices at the Health, Education, Labor and Pensions Committee.

The summer’s good will soon gave way to autumn intrigue: After months of toying with the idea of running in 2018 to become Maine’s first female governor, Collins spent all of September and half of October mulling her future.

For weeks, other candidates – some declared, some not – watched and waited. Pundits far and wide agreed that the governorship, were she so inclined, was Collins’ for the asking.

Finally, on Oct. 13, in a Rockport ballroom packed with state and national media, Collins announced she would remain in the Senate. Her chamber-of-commerce audience rose as one and cheered.

That moment, graciously passing on the Blaine House while basking in appreciation for her pivotal role in the Senate, would prove the high point of her year.

As Republicans in Congress set aside health care and shifted their focus to tax reform, Collins once again found herself under a magnifying glass.

Flanked by Sen. Rand Paul of Kentucky, left, and Sen. Bill Cassidy, Collins asks questions of a panel during a hearing of the Health, Education, Labor and Pensions Committee.

Would she, as many in her newly expanded base hoped, stand up to leadership in the face of massive tax cuts for corporations and the wealthy, just as she had held her ground with Obamacare?

Or would she fall in line with her party and vote out the tax cuts – which she has long supported – even as protesters occupied her offices across Maine and social media once again inundated her with pleas that she stand firm?

The din only intensified when Republicans in the House and Senate agreed to include the repeal of Obamacare’s individual mandate in the tax bill. Many fear that the loss of that provision, which holds down premiums by requiring that all Americans obtain health insurance or pay a penalty, spells the beginning of the end for Obamacare itself.

Collins, caught between a Republican base that no longer trusted her and a newfound cadre of independent and Democratic supporters who read perhaps too much into her summer conversion, sat down with Republican leaders in the Senate and hammered out a deal.

Standing in an elevator at the Capitol, Collins is asked questions by reporters while on her way back to her office.

In exchange for her “yes” vote, she got three amendments tacked onto the tax bill: a personal income-tax deduction for state and local taxes capped at $10,000, an expanded deduction for major medical expenses, and a relaxation of catch-up contribution limits on nonprofit and public retirement plans.

Collins also obtained written commitments from congressional leaders that automatic Medicare cuts, triggered by the tax bill, would not happen.

Finally, she secured Senate Majority Leader Mitch McConnell’s pledge that two bipartisan bills – both aimed at shoring up Obamacare following the loss of the individual mandate – would be passed by year’s end.

“If this commitment is not kept to me, believe me, there will be consequences. There really will be,” Collins vowed that day in her office, a week before the final vote on the tax bill. “I mean, I can’t not have the commitment happen.”

She had good reason: Throughout Washington, D.C., from the cable news shows to a Dec. 11 Washington Post editorial headlined “Susan Collins is getting it wrong,” a narrative emerged that McConnell and his Republican cohorts had played Collins like a fiddle.

The strain on Collins was evident when, four days later, she complained to the press gaggle outside her office that news coverage of her efforts was “unbelievably sexist.” She cited, in particular, one reporter who wrote that she “didn’t cry” during a meeting with constituents suffering from serious health issues.

“I can’t imagine a reporter writing that about a male senator meeting with the same group,” she admonished the media horde.

Just hours later, the tax bill passed with Collins’ amendments attached.

Almost simultaneously, to the surprise of few besides Collins, votes on the Obamacare rescue bills were put off until next year.

Collins, deluged by a chorus of “I told you so’s,” shifted immediately into damage control.

“I think the policy is more important than the deadline,” she said by phone from Capitol Hill shortly after announcing the postponement. “The deadline is slipping, and I am the first to say that I am not happy about that, that I’m disappointed about that. But I believe that at the end of the day, we’re going to end up where I want us to be.”

Collins takes a rare walk alone down a hall of the Dirksen Office Building on her way to a Intelligence Committee briefing.

On that, only time will tell.

Yet even now, after a year that saw her stock rise and fall repeatedly across the political spectrum, all eyes remain on the senior senator from Maine. Her swing-vote leverage will only increase with the arrival of Democrat Doug Jones of Alabama to take the seat once occupied by Collins’ old friend Sessions, leaving the Senate Republicans with a precarious 51-vote majority.

Collins talks with Republican Sen. Bill Cassidy of Louisiana during a committee hearing.

To many of her colleagues, if not most of her constituents, Collins had a choice this month: Cast a protest “no” vote and watch a historic tax cut pass anyway; or do what she could to improve it and risk having it all backfire on her in the end.

“She made the best out of what she had to work with there,” Sen. Joe Manchin, D-West Virginia, who voted against the tax bill, said earlier this month. “I don’t look at her as Susan Collins, Republican from Maine. I look at her as Susan Collins, my friend who wants to get something done in Washington.”

Closer to home, Sen. King shares that view.

While a simple “no” vote by Collins on the tax package might have won her more newfound accolades for standing up to her party, King noted that it wouldn’t have improved the legislation in the ways her amendments did.

“That’s a tough call in this business,” said King, who also opposed the tax bill. “You’ve got to listen to your constituents … but you’ve also got to do what you think is right.”

Collins insists that’s what she did all year – from the new president with the runaway mouth, to the airport applause, to the gubernatorial campaign that wasn’t, to the deadline that came and went while her credibility teetered in the balance.

Yes, she said in answer to the question, she hears the criticism.

“Do I enjoy it? When I got my morning paper today and I got to the editorial page, did it make me happy as I’m eating my yogurt and getting ready to go? No,” she said with a rueful smile. “It’s hard, no matter how thick you try to make your skin. It still…it still …”

Stings?

” ‘Stings’ is an excellent word,” Collins replied. “But I’ve learned it goes with the job.”