Maine Sen. Susan Collins’ announcement that she would not vote for Donald Trump reverberated across the political landscape Tuesday, with many who study politics saying the timing couldn’t be worse for the Republican presidential nominee or better for his Democratic rival, Hillary Clinton.

In a withering opinion column in The Washington Post first published online late Monday, Collins denounced Trump and said she won’t vote for Clinton.

The announcement followed a two-week slump in the polls for Trump, who also faced fresh criticism from 50 former advisers to U.S. presidents on foreign affairs and national security.

Collins’ rebuke was also the latest criticism from leading Republican women in Congress and is unlikely to improve Trump’s chances with female voters, a demographic that polls show he is already struggling to win over.

Michele Swers, a professor of government at Georgetown University who focuses on women in congressional politics, was not surprised by Collins’ strong statement against Trump given the differences between the two.

“She has built her brand on being a consensus builder – being part of deals that end government shutdowns or budget stalemates,” said Swers, author of the book “Women in the Club: Gender and Policy Making in the Senate.” “Her whole persona is built on being a different kind of politician … and Donald Trump is everything the opposite. Tearing down the political establishment is what he wants do to.”

Swers noted that Collins received national media exposure as the latest of several Republican women speaking out against Trump, including former first lady Barbara Bush and Hewlett Packard CEO Meg Whitman.

“(Collins’ statement) could contribute to the groundswell of a story line,” she said. But that doesn’t mean it will convince a Republican woman in say, Iowa, to change her position regarding Trump, Swers said.

Brian Duff, an associate professor of political science at the University of New England, said Collins’ announcement puts Trump’s campaign back on the defensive after Trump had tried to reset 10 days of political missteps with a speech on his plan to improve the American economy at an appearance Monday in Detroit. The most recent national polls suggest voters now favor Clinton by at least 10 points, well beyond the polls’ margins of error.

Duff said voter positions tend to solidify in the weeks after national conventions, so the timing of Collins’ announcement puts her opposition to Trump in the spotlight and benefits Clinton.

“Susan Collins has a better national reputation than any of the other Republicans that are siding with Trump,” he said, “so this has the potential to be quite significant.”

COLLINS FELT DUTY TO DO ‘RIGHT THING’

Collins announced her opposition to Trump at a time when one of her few Republican colleagues from New England, Sen. Kelly Ayotte of New Hampshire, is fighting to keep her job.

Ayotte has tried to appease Trump’s base in New Hampshire by saying she will support the nominee, even as she has refrained from endorsing him. Democrats backing her opponent, Gov. Maggie Hassan, are trying to capitalize on Trump’s unpopularity among other New Hampshire voters by portraying Ayotte as his ally.

Dante Scala, an associate professor of political science at the University of New Hampshire, said Collins’ denouncement of Trump could resonate with some moderate or independent-leaning Republicans in New Hampshire, a state that Trump won by a landslide in the February primary but is now polling for Clinton.

“It’s been a rough month for those types of folks who don’t like Hillary Clinton, who would typically vote Republican but don’t like Donald Trump,” Scala said. “I don’t think Senator Collins is going to move a lot of votes in New Hampshire. But I think it is one more reason for a New Hampshire Republican to say to herself or himself, ‘Well, I have one more good reason not to vote for Donald Trump.’ ”

In a phone interview Tuesday with the Portland Press Herald, Collins said her intent wasn’t to bolster Clinton’s lead in the polls or to sway others to jump on a dump-Trump bandwagon. Collins said she ultimately felt a responsibility to herself and the Republican Party to come out against Trump, and she understands there may be political consequences for that decision.

“I think Mainers and my colleagues in the Senate know that I did it because I felt like it was the right thing to do,” Collins said. “I hope people will respect that, and if they don’t, I’m prepared to accept the consequences because it is the right thing to do. If you are going to be in public life, the point of it is to do what you think is right, and I gave Donald Trump many chances to improve or change or retract his words and he just never did.”

While she had plenty to criticize Trump for, she also noted that he has tapped into an undercurrent of discontent in American society and understands better than Clinton that there is a large bloc of Americans who feel like they are being left out or left behind. When pressed, Collins said Clinton had the skills and experience to lead the U.S. on the global stage – one of her key reservations about Trump.

SO WHOM WILL COLLINS VOTE FOR?

“My decision was my own,” Collins said when a CNN interviewer asked whether she was influenced by anyone else. “It certainly was informed by my many years that I served as the chairman of Senate Homeland Security (committee), as well as the regular briefings that I receive now as a member of the Intelligence Committee.” She said those top-secret four-hour briefings, twice a week, offer a clear view of the threats to the U.S. and other countries around the globe.

In her column, Collins said she was “deeply concerned” that Trump’s “lack of self-restraint and his barrage of ill-informed comments would make an already perilous world even more so.”

She also said promises that Clinton made to bolster the U.S. economy and grow jobs through new government programs and infrastructure investments couldn’t be kept and would only add to the national debt, which exceeds $17 trillion.

In an appearance on CNN, Collins said she is contemplating a write-in candidate or a vote for the Libertarian Party’s ticket, which includes former New Mexico Gov. Gary Johnson as the presidential nominee with former Massachusetts Gov. Bill Weld as vice president.

However, she has some reservations about Johnson based on his support of marijuana legalization and other statements he’s made about his own drug use.

“If the Libertarian ticket were reversed, with Gov. Bill Weld leading that ticket, then I would vote for the Libertarian ticket,” Collins said, “because I know Bill Weld well and I respect him a great deal.”

In Maine, the leaders of the state’s Republican and Democratic parties offered mixed reactions to Collins’ announcement on Trump.

Maine Republican Party Chairman Rick Bennett issued a statement that did not mention Collins or Trump, but said the party embraces diverse opinions.

“We are blessed with a broad, open-minded party representing myriad views on specific issues and candidates,” Bennett said. “I have always encouraged our activists to work hard for those Republican candidates they support, and not work against those they don’t support. This is the best way to give our party the definition desired.”

PRAISE AND CRITICISM FROM PUBLIC

In a written statement, Maine Democratic Party Chairman Phil Bartlett said, “I commend Sen. Collins for refusing to support Donald Trump’s candidacy, although I do question why it took her so long to find the courage to do so.”

He urged Collins to “demonstrate the courage of her convictions by supporting Hillary Clinton, rather than just sitting this one out and tacitly helping Trump’s candidacy.”

While that is an unlikely scenario for the lifelong Republican from northern Maine, those who study politics said Tuesday that the timing of Collins’ decision could help solidify Clinton’s current lead in the polls.

Like their party leaders, Maine voters, state lawmakers and former lawmakers had mixed reactions to Collins’ decision.

Helen Hall of Gray called the Press Herald to say that Collins had lost her support. “She will never ever get my vote again,” Hall said.

But David Giansiracusa of Portland wrote to express his support for Collins. “I truly agree with Sen. Collins’ sentiments and will contact her to thank her for giving voice to her thoughts and feelings,” Giansiracusa said in an email to the newspaper.

Former state Senate President Kevin Raye, a Republican and ardent Collins supporter, defended her decision on Twitter. “Ironic that angry Trumpers berate (Sen. Collins) for not endorsing one R nominee after Trump’s lifetime support and $ for D nominees,” Raye tweeted.

Sen. Roger Katz, R-Augusta, who also recently announced he wouldn’t vote for Trump, wrote a short email message – “My only thought: I’m proud that she’s our senator.”

But state Rep. Sheldon Hanington, R-Lincoln, called the George Hale and Ric Tyler talk show on radio station WVOM in Bangor to say that while Collins has a right to vote for whom she wants, she shouldn’t try to influence others to not support the party’s candidate.

“It’s her prerogative, if she wants to not vote for Trump. But like myself, I voted for Trump in the caucus, but I didn’t let people know until after he got the nomination,” Hanington said. “I think it’s fair game, but I don’t think you ought to use it for influence – just my opinion.”