The Senate voted 51-48 to break a Democratic filibuster of Barrett's nomination, setting up a likely final vote to confirm President Donald Trump's selection to replace the late Justice Ruth Bader Ginsburg on Monday.
Sens. Lisa Murkowski, R-Alaska, and Susan Collins, R-Maine, joined Democrats in voting to maintain the filibuster while Sen. Kamala Harris, D-Calif, was in Michigan campaigning as the Democratic vice presidential nominee and did not vote.
Just 51 of the 53 Republicans in the Senate must vote in favor of Barrett's confirmation to secure her spot on the court.
Collins is expected to vote against confirming Barrett, while Murkowski, who was previously undecided, said she would vote to confirm her.
"I believe that the only way to put us back on the path of appropriate consideration of judicial nominees, is to evaluate Judge Barrett as we would want to be judged -- on the merits of her qualification," said Murkowski. "And we do that when that final question comes before us. And when it does, I will be a yes."
Barrett's confirmation would give conservatives a 6-3 ideological majority on the Supreme Court and her nomination has faced resistance from Democrats who believe the decision of filling Ginsburg's seat on the court should be made by the winner of November's election.
Democratic presidential nominee Joe Biden has warned that Barrett's confirmation could spell an end for the Affordable Care Act, the healthcare law he helped to put in place while serving alongside President Barack Obama.
Others have also expressed concern that a conservative majority may threaten the landmark abortion case Roe vs. Wade.