Mitt Romney, Susan Collins and Ben Sasse have been outspoken about Trump's challenges to the election results, while most other Republican senators have not.
Collins had been tipped to lose her seat, with polls largely leaning against her in the run-up to the vote.
The Maine senator is only 1 point behind Democratic candidate Sara Gideon after her vote against Amy Coney Barrett's nomination.
The poll, which was conducted by Colby College in Maine, found Gideon, leading by four points, as 47 percent said they'd vote for her, while 43 percent sided with Collins.
Democrats need to gain at least four seats to take control of the Senate.
The Maine Republican voted with all 47 members of the Democratic Caucus against the conservative Trump nominee.
Though Sen. Lisa Murkowski of Alaska had previously said she would vote against Barrett because the hearings were before the election, on Saturday she announced she had changed her mind.
The Senate has 35 seats up for grabs in the 2020 election, with 23 of those now belonging to the GOP.
Last month, through her personal action committee,Dirigo PAC, Senator Susan Collins, a Republican from Maine, contributed $400 each to the campaigns of Kevin Bushey and Brian Redmond.
Senator Collins has split with President Trump on several issues: the nomination of Amy Coney Barrett to the Supreme Court, his stance on health care and the opening up of 5,000 square miles of water to commercial fishing, which would roll back protection at a marine conservation area near Maine.
At least eight GOP incumbents are in danger of losing their seats, while just one Democrat looks likely to be ousted.
"We all need to keep working until we reach a bipartisan agreement that can pass both chambers and be signed by the president," Senator Lisa Murkowski said.
GOP Senator Susan Collins broke with President Donald Trump over his decision to kill stimulus negotiations until after November 3.
Democrats need to gain at least four seats to take control of the upper chamber of Congress from the GOP.
"I want to cut these masks right in front of our viewers," Max Linn said as he sliced face coverings into pieces with a pair of scissors.
"We're simply too close to the election, and in the interest of being fair to the American people," the Republican senator said.
Maine will be the first state in U.S. history to use this voting process in a presidential election.
"I think it is particularly important that the Senate take it up and confirm this nomination before the election," the Texas Republican said.
"I did not support taking up a nomination eight months before the 2016 election to fill the vacancy created by the passing of Justice Scalia," the Republican senator from Alaska said.
Arizona Sen. Martha McSally was 8 points behind Democratic candidate Mark Kelly in the same week he had to apologize for a racist joke.
The Republican-proposed $500 billion stimulus deal left out provisions for another round of stimulus checks. It was defeated by Democrats.
Sen. Susan Collins (R-Maine) said that President Donald Trump "should have been straightforward with the American people" about the "hard facts" of the COVID-19 pandemic on Friday.
Democrats would need to win at least four Republican seats while maintaining all their current seats to take control of the upper chamber of Congress.
Sen. Susan Collins' reelection campaign posted a photo to social media that appears to feature a campaign sign for President Donald Trump that was digitally blurred out.
Maine House Speaker Sara Gideon has an eight-point lead of incumbent Republican Senator Susan Collins.
Based on polling, the contest is still too close to call, according to Quinnipiac University.
Obama said the people he was endorsing made him "optimistic" about the country's future long after November's election.
Republican Senator Susan Collins of Maine, on Wednesday, released a new campaign video, saying she won't "back down" after the Lincoln Project spends $1 million on ads attacking her.
Poll data indicated that 51 percent of Maine voters held an unfavorable opinion about Republican Senator Susan Collins.
Senate Republican Party campaigns have broken multiple fundraising records this year as they look to hold onto their slim majority.