Sen. Joe Manchin announced Friday morning he intends to vote for Supreme Court nominee Ketanji Brown Jackson, boosting her chances of being confirmed.

“After meeting with her, considering her record, and closely monitoring her testimony and questioning before the Senate Judiciary Committee this week, I have determined I intend to vote for her nomination to serve on the Supreme Court,” Manchin, D-W.Va, said.

Manchin’s vote is noteworthy because Jackson can be confirmed without any Republican support if all 50 Senate Democrats vote for her. One of the most conservative Democrats in the Senate, Manchin has sometimes broken with his party, most recently sinking President Joe Biden’s Build Back Better legislation.

Manchin called Jackson’s record and career “exemplary,” citing her rise from the public school systems to Harvard Law School. He also referenced her work as a clerk to three federal judges, as well as in private law firms, on the U.S. Sentencing Commission, a federal public defender, and a district and appeals court judge.

“Her wide array of experiences in varying sectors of our judicial system have provided Judge Jackson a unique perspective that will serve her well on our nation's highest court,” Manchin said.

“I am confident Judge Jackson is supremely qualified and has the disposition necessary to serve as our nation's next Supreme Court justice,” he added.

Jackson, who would become the first Black woman to be appointed to the Supreme Court, sat through two days of sometimes bruising questioning during her Senate Judiciary Committee hearings this week. While she appears to enjoy broad support from Democrats, Republicans grilled her on what they characterized as her light sentencing in child pornography cases, her representation of Sept. 11 terror suspects as a public defender and critical race theory.

Jackson called child pornography a “sickening and egregious crime,” but argued, in the internet age, current sentencing guidelines don’t adequately differentiate between the most serious and less serious offenders. She defended her work with Guantanamo Bay detainees, saying public defenders do not get to pick their cases and that every suspect is entitled to legal representation under the Constitution. And she insisted critical race theory does not intersect with her work as a judge.

On Thursday, just hours after the hearings came to a close, Senate Republican Leader Mitch McConnell announced he will vote against Jackson's confirmation. He said in a Senate floor speech that he “cannot and will not” support her for a lifetime appointment.

McConnell slammed the liberal groups that have supported Jackson, and he criticized her for refusing to take a position on the size of the nine-member court, even though that decision is ultimately up to Congress. Some advocacy groups have pushed for enlarging the court after three justices nominated by former President Donald Trump cemented a 6-3 conservative majority.

One or more Republicans could still cast a vote for Jackson’s confirmation, but the contentious nature of the four-day hearings laid bare a familiar partisan dynamic, seen over years of pitched fighting over judicial nominations.

Senate Judiciary Committee Chairman Dick Durbin, who has been privately lobbying GOP colleagues to support Jackson, said after McConnell’s announcement that it will be “sad for our country and sad as a commentary on where the parties are today” if her historic nomination is approved on a strictly partisan vote. “The Republicans are testing their messages for the November election,” Durbin said.

Durbin said he is “still hoping that several Republicans — I hope many more” will vote for her.

The Associated Press contributed to this report.