Sen. Susan Collins Susan Margaret CollinsSenate Republicans face tough decision on replacing Ginsburg Democratic senator calls for eliminating filibuster, expanding Supreme Court if GOP fills vacancy What Senate Republicans have said about election-year Supreme Court vacancies MORE is walking a fine line in President Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE's Senate impeachment trial: The moderate Maine Republican has to demonstrate some independence from the president, but she can’t run too far away from him and alienate GOP voters.

One of the most vulnerable lawmakers up for reelection this fall, Collins was the only GOP senator early Wednesday morning to break with her party and back a proposed rules change offered by Senate Minority Leader Charles Schumer Chuck SchumerPelosi orders Capitol flags at half-staff to honor Ginsburg Ginsburg in statement before her death said she wished not to be replaced until next president is sworn in Democrats call for NRA Foundation to be prohibited from receiving donations from federal employees MORE (D-N.Y.).

Collins was also among the small band of centrist Republicans who successfully pressured Senate Majority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE (R-Ky.) to alter the trial rules in favor of greater transparency.

ADVERTISEMENT

Yet Collins also joined Republicans on 10 other votes that blocked Democratic amendments, proving to be a loyal foot soldier on the majority of the votes.

All of these headline-grabbing actions underscored the strange position Collins finds herself in as she seeks her fifth term in the battleground state of Maine, which favored Hillary Clinton Hillary Diane Rodham ClintonWhat Senate Republicans have said about election-year Supreme Court vacancies Bipartisan praise pours in after Ginsburg's death Trump carries on with rally, unaware of Ginsburg's death MORE by nearly 3 percentage points in 2016 but maintains strong support for Trump among its Republican base.

That balancing act is nothing new for Collins, who has burnished a reputation as a moderate — critics say undeservingly — even as she’s historically been a reliable vote for the agenda of party leaders.

“Susan always does what’s best for her constituents, and then she explains it really well,” Sen. Kevin Cramer Kevin John CramerOn Paycheck Protection Program, streamlined forgiveness is key McConnell shores up GOP support for coronavirus package Army Corps urges DOJ to settle case with ND over M DAPL damages MORE (R-N.D.), a Trump ally, told The Hill on Wednesday. “I’m sure it didn’t hurt her any; I’m sure it helped her. She’s a very courageous Republican.”

Her fellow Maine senator, Independent Angus King Angus KingShakespeare Theatre Company goes virtual for 'Will on the Hill...or Won't They?' On The Trail: How Nancy Pelosi could improbably become president Angus King: Ending election security briefings 'looks like a pre-cover-up' MORE, declined to comment about Collins’s political motivations for breaking with her party and Trump, whose disapproval rating in Maine sits at 52 percent, according to a recent Morning Consult poll.

But King praised the rules changes that Collins and Sens. Lisa Murkowski Lisa Ann MurkowskiSenate Republicans face tough decision on replacing Ginsburg What Senate Republicans have said about election-year Supreme Court vacancies McConnell says Trump nominee to replace Ginsburg will get Senate vote MORE (R-Alaska) and Rob Portman Robert (Rob) Jones PortmanRomney undecided on authorizing subpoenas for GOP Obama-era probes Congress needs to prioritize government digital service delivery House passes B bill to boost Postal Service MORE (R-Ohio) helped secure from McConnell during a private lunch on Tuesday. The last-minute changes allowed for evidence from the House investigation to be automatically admitted to the Senate trial and extended the number of days for both the prosecution and defense teams to make their arguments.

ADVERTISEMENT

“It was a good change. It solved two of the three problems with the rules,” King, who defeated Collins in the 1994 race for the Maine governor’s mansion, told The Hill. “Unfortunately, it didn’t solve the problem of reversing the witness-calling piece but at least got the record squared away of not [having] such long, 12-hour days” for opening arguments.

Democrats remain highly skeptical of Collins, doubtful she will ultimately side with them on upcoming critical votes to call witnesses and convict Trump.

They say they plan to use her past impeachment remarks — as well as her vote to confirm Supreme Court Justice Brett Kavanaugh Brett Michael KavanaughProgressive group to spend M in ad campaign on Supreme Court vacancy Senate Republicans face tough decision on replacing Ginsburg Trump reacts to Ginsburg's death: 'An amazing woman who led an amazing life' MORE — to paint the moderate senator as increasingly political and partisan.

It “speaks to a larger argument about Collins that she has changed during the couple of decades that she’s been in Washington and become more partisan, more political,” said a Democratic strategist.

The impeachment proceedings in the Senate come as recent polling shows the senator’s support declining among voters in the Pine Tree State. A Morning Consult poll released last week showed Collins as the most unpopular senator in the chamber, with a 52 percent disapproval rating, handing Democrats an obvious opening.

Collins is facing five Democratic challengers, including Maine House Speaker Sara Gideon.

Moreover, a poll commissioned by Senate Majority PAC, a super PAC dedicated to helping Democrats, found that 51 percent of Maine voters said that if Collins votes to acquit Trump, she would be doing so for political purposes.

The same poll also showed a majority of voters believe Trump abused his power by pressuring Ukraine to investigate former Vice President Joe Biden Joe BidenSenate Republicans face tough decision on replacing Ginsburg What Senate Republicans have said about election-year Supreme Court vacancies Biden says Ginsburg successor should be picked by candidate who wins on Nov. 3 MORE, a top political rival.

The Democratic Senatorial Campaign Committee is salivating at the chance to hit Collins over impeachment. The Democrats’ campaign arm this month launched a website drawing attention to remarks Collins made during former President Clinton's impeachment trial in the late 1990s and comparing them to her statements about Trump’s trial in the Senate.

The website, titled WhatChangedSusan.com, highlights comments from Collins in 1999, when she said she needed “witnesses and further evidence” for the Senate “to get to the truth” so it could carry out its “duty to do impartial justice.”

Collins later voted against impeaching Clinton.

Republicans say the move by Democrats to bring impeachment into the 2020 election is a miscalculation, arguing that it's not front of mind for voters in Maine.

“This impeachment thing is going to be a nothingburger,” a Republican strategist told The Hill. “That’s not where the debate is right now” in Maine.

“We’re talking about ethics. We’re talking about taxes. We’re talking about health care. Those are the issues people actually care about,” the strategist continued.

Collins has been widely praised for being a maverick figure in the past. She notably bucked her own party in 2017 when she voted against Republican efforts to repeal and replace the Affordable Care Act.

However, her vote to confirm Kavanaugh in 2018 led to a number of progressive groups taking aim at Collins, vowing to unseat her.

The most recent group, Demand Justice, targeted Collins in an ad Tuesday over her vote to confirm Kavanaugh over a year ago.

“For so long, she when combined with [former] Sen. Olympia Snowe [R-Maine] were these Maine state treasures who had built a lot of trust and a lot of love and a lot of regard in Maine and across the country,” Democratic strategist Jon Reinish told The Hill.

ADVERTISEMENT

“Over the last couple of years, Susan Collins has very, very demonstrably strayed from that past,” he continued. “I don’t know whether it’s true colors coming out at the end of her career or the pressure of having a Republican president, and then being in the majority.”

Still, Republicans say that Collins’s decision on these issues is not necessarily going to cost her swing votes in the state.

“If someone’s not voting for Susan Collins because of Brett Kavanaugh, they probably weren’t going to vote for her anyways,” the GOP strategist said.

Jordain Carney contributed to this report.