Senate Majority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellMomentum growing among Republicans for Supreme Court vote before Election Day Trump expects to nominate woman to replace Ginsburg next week Video of Lindsey Graham arguing against nominating a Supreme Court justice in an election year goes viral MORE (R-Ky.) on Friday praised Sen. Susan Collins Susan Margaret CollinsJeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Trump supporters chant 'Fill that seat' at North Carolina rally Momentum growing among Republicans for Supreme Court vote before Election Day MORE (R-Maine) for deciding to stay in the Senate and pass on a bid for governor.

"Senator Collins lives up to her state motto, Dirigo, every day in the Senate," McConnell said in a statement. "She never misses votes. She fights fiercely for her constituents. She brings conviction, smarts, and leadership to every issue.

"Her decision to remain in the Senate is important not only for the people of Maine, who she serves so well, but for the nation as a whole."

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McConnell's praise comes even though Collins was one of three Republicans to thwart the majority leader by voting against the GOP's effort to repeal and replace ObamaCare.

Collins was joined by Sens. Lisa Murkowski Lisa Ann MurkowskiMomentum growing among Republicans for Supreme Court vote before Election Day Collins: President elected Nov. 3 should fill Supreme Court vacancy Barrett seen as a front-runner for Trump Supreme Court pick MORE (R-Alaska) and John McCain John Sidney McCainMomentum growing among Republicans for Supreme Court vote before Election Day McConnell urges GOP senators to 'keep your powder dry' on Supreme Court vacancy McSally says current Senate should vote on Trump nominee MORE (R-Ariz.) to defeat a so-called skinny repeal bill.

On Friday, Collins said she would not run for governor of Maine, ending months of speculation that she would leave the upper chamber.

She attributed her decision to a desire to play a "key role" in major policy debates.

"I want to continue to play a key role in advancing policies that ... bring peace and stabilities to a troubled and violent world," Collins said in an announcement Friday. "And I have concluded that the best way I can contribute to these priorities is to remain a member of the U.S. Senate."

She also addressed the Senate's ObamaCare effort, saying it was crafted in secrecy and without public input.

“The Senate Republican health-care bills were drafted behind close doors. By the way, it was a group of 13 men who did it,” Collins said. “It completely bypassed the standard legislative process.”

Collins's decision to stay in the upper chamber is also a boost for centrist Republicans, who have seen their ranks hit by a number of planned retirements.

Collins is next up for reelection in 2020.