WASHINGTON — Maine Sen. Susan Collins said Wednesday she will vote to confirm Judge Ketanji Brown Jackson, giving Democrats at least one Republican vote and all but assuring that Jackson will become the first Black woman on the Supreme Court.

Collins met with Jackson a second time after four days of hearings last week and said Wednesday that “she possesses the experience, qualifications, and integrity to serve as an associate justice on the Supreme Court.”

“I will, therefore, vote to confirm her to this position,” Collins said.

Collins’ support gives Democrats at least a one-vote cushion in the 50-50 Senate and likely saves them from having to use Vice President Kamala Harris’ tie-breaking vote to confirm President Joe Biden’s pick. Senate Democratic leaders are pushing toward a Senate Judiciary Committee vote on the nomination Monday and a final Senate vote to confirm Jackson late next week.

White House chief of staff Ron Klain tweeted that he was “grateful” to Collins for “giving fair, thoughtful consideration” to Jackson and to other lower court nominees she has supported.

Jackson, who would replace retiring Justice Stephen Breyer, would be the third Black justice, after Thurgood Marshall and Clarence Thomas, and the sixth woman. She would also be the first former public defender on the court.

It is expected that all 50 Democrats will support her, though one notable moderate Democrat, Arizona Sen. Kyrsten Sinema, hasn’t yet said how she will vote.

Collins was the most likely Republican to support Jackson, and she has a history of voting for Supreme Court nominees picked by presidents of both parties, as well as other judicial nominations.

The only Supreme Court nominee she’s voted against since her election in the mid-1990s is Justice Amy Coney Barrett, who was nominated by then-President Donald Trump after the death of Justice Ruth Bader Ginsburg in the weeks before Trump’s election defeat to Biden in 2020. Collins, who was up for reelection that year, said she voted against Barrett because of the accelerated six-week timeline. “It’s not a comment on her,” Collins said of Barrett at the time.

In her statement supporting Jackson, the Maine senator said she doesn’t expect that she will always agree with Jackson’s decisions.

“That alone, however, is not disqualifying,” Collins said. “Indeed, that statement applies to all six justices, nominated by both Republican and Democratic presidents, whom I have voted to confirm.”

Collins said she believes the process is “broken” as it has become increasingly divided along party lines. When Collins first came to the Senate, Supreme Court confirmations were much more bipartisan. Breyer, who will step down this summer, was confirmed on an 87-9 vote in 1994.

“In my view, the role the Constitution clearly assigns to the Senate is to examine the experience, qualifications, and integrity of the nominee,” Collins said. “It is not to assess whether a nominee reflects the ideology of an individual senator or would rule exactly as an individual senator would want.”

In Jackson’s hearings, several Republican senators interrogated her on sentencing decisions in her nine years as a federal judge and in child pornography cases in particular. The senators, several of whom are eyeing a run for president, asked the same questions repeatedly in an effort to paint her as too lenient on sex criminals.

Jackson told the committee that “nothing could be further from the truth” and explained her sentencing decisions in detail. She said some of the cases have given her nightmares and were “among the worst that I have seen.”

Collins said that in her meetings with Jackson, “we discussed in depth several issues that were raised in her hearing. Sometimes I agreed with her; sometimes I did not.”

It is unclear if any other GOP senators will vote for Jackson. Senate Republican Leader Mitch McConnell set the tone for the party last week when he said he “cannot and will not” support her, citing the GOP concerns raised in the hearing about her sentencing record and her support from liberal advocacy groups.

Jackson is still making the rounds in the Senate ahead of next week’s votes, doing customary meetings with Democratic and Republican senators. On Tuesday she met with Utah Sen. Mitt Romney, who said afterward that he was undecided about supporting her.

Romney said he had an “excellent meeting” and found Jackson to be intelligent, capable and charming.

“I enjoyed our discussion a great deal,” the Republican senator told reporters. “I haven’t made a decision. When I do, I’ll let you know. Probably not until the day of the vote.”

Romney voted against Jackson last year, when she was confirmed by the Senate as a federal appeals court judge. Collins, Alaska Sen. Lisa Murkowski and South Carolina Sen. Lindsey Graham were the only three Republicans to support her at the time.

Graham and Murkowski have indicated they might vote against her now. Murkowski said in a statement before the hearings that “I’ve been clear that previously voting to confirm an individual to a lower court does not signal how I will vote for a Supreme Court justice.”

Graham was one of several Republicans on the Judiciary panel who pressed Jackson on the child pornography cases, and he has been vocal in his frustrations that Biden chose Jackson over his preferred candidate, a federal judge from South Carolina.

He also aired past grievances in the hearing, asking Jackson about her religion and how often she goes to church, in heated comments that he said were fair game after unfair criticism of Barrett’s Catholicism.