WASHINGTON — Longtime liberal Supreme Court Justice Stephen Breyer is retiring, numerous sources said Wednesday, giving President Joe Biden his first high court opening, which he has pledged to fill with the historic naming of the court's first Black woman.

Breyer, 83, has been a pragmatic force on a court that has grown increasingly conservative, trying to forge majorities with more moderate justices right and left of center. His retirement will give Biden the chance to name and win confirmation of a replacement before next fall's election when Republicans could retake the Senate and block future nominees.

Democrats are planning a swift confirmation, perhaps even before Breyer officially steps down, which is not expected before summer.

He has been a justice since 1994, appointed by President Bill Clinton. Along with the late Justice Ruth Bader Ginsburg, he opted not to step down the last time the Democrats controlled the White House and the Senate during Barack Obama’s presidency. Ginsburg died in September 2020, and then-President Donald Trump filled the vacancy with a conservative justice, Amy Coney Barrett.

Breyer’s departure won’t change the 6-3 conservative advantage on the court because his replacement will almost certainly be confirmed by a Senate where Democrats have the slimmest majority. It will make conservative Justice Clarence Thomas the oldest member of the court. Thomas turns 74 in June.

Senate Majority Leader Chuck Schumer said Biden’s nominee “will receive a prompt hearing in the Senate Judiciary Committee and will be considered and confirmed by the full United States Senate with all deliberate speed.” A White House decision on a nominee could take several weeks, Biden aides and allies said.

Republicans who changed the Senate rules during the Trump era to allow simple majority confirmation of Supreme Court nominees appeared resigned to the outcome.

Sen. Lindsey Graham of South Carolina, the top Republican on the Senate Judiciary Committee, said in a statement: “If all Democrats hang together — which I expect they will — they have the power to replace Justice Breyer in 2022 without one Republican vote in support."

Liberal interest groups expressed relief. They have been clamoring for Breyer’s retirement, concerned about confirmation troubles if Republicans retake the Senate.

"Justice Breyer’s retirement is coming not a moment too soon, but now we must make sure our party remains united in support of confirming his successor,” Demand Justice Executive Director Brian Fallon said.

Among the names being circulated as potential nominees are California Supreme Court Justice Leondra Kruger, U.S. Circuit Judge Ketanji Brown Jackson, prominent civil rights lawyer Sherrilyn Ifill and U.S. District Judge Michelle Childs, whom Biden has nominated to be an appeals court judge. Childs is a favorite of Rep. James Clyburn, D-S.C., who made a crucial endorsement of Biden just before South Carolina's presidential primary in 2020.

Biden's pledge to name the first Black woman to the Supreme Court was made during the 2020 presidential campaign. Since he took office a little more than a year ago, he has been focused on increasing racial, ethnic and experiential diversity in the lower federal courts. He has doubled the number of Black women who serve on appellate courts just below the Supreme Court, with three more nominees pending.

Democratic Rep. Joyce Beatty of Ohio, the chairwoman of the Congressional Black Caucus, said, “We know that when America’s boardrooms, legislatures and even the Supreme Court start to resemble America, we all benefit."

Nomination of a Black woman could also help Biden politically with some of the Democratic Party's most important Election Day supporters. He has been criticized by black leaders and groups for failing so far to persuade the Senate to pass legislation shoring up voting rights that are being restricted in a number of Republican-led states.

Change comes slowly to the Supreme Court. Of the 115 justices in U.S. history, there have been just five women, beginning with Sandra Day O'Connor in 1981. One of the five, Justice Sonia Sotomayor is a Latina. Thomas and the late Thurgood Marshall are the only two Black men who have served on the court.

The president wouldn't address reports of Breyer's retirement on Wednesday.

“Every justice should have an opportunity to decide what he or she is going to do and announce it on their own," Biden said. “Let him make whatever statement he’s going to make and I’ll be happy to talk about it later.”

Often overshadowed by his fellow liberal Ginsburg, Breyer authored two major opinions in support of abortion rights on a court closely divided over the issue, and he laid out his growing discomfort with the death penalty in a series of dissenting opinions in recent years.

Breyer’s views on displaying the Ten Commandments on government property illustrate his search for a middle ground. He was the only member of the court in the majority in both cases in 2005 that barred displays in two Kentucky courthouses but allowed one to remain on the grounds of the state Capitol in Austin, Texas.

In more than 27 years on the court, Breyer has been an active and cheerful questioner during arguments, a frequent public speaker and quick with a joke, often at his own expense. He made a good natured appearance on a humorous National Public Radio program in 2007, failing to answer obscure questions about pop stars.

He is known for his elaborate, at times far-fetched, hypothetical questions to lawyers during arguments and he sometimes has had the air of an absent-minded professor. He taught antitrust law at Harvard earlier in his professional career.

He also spent time working for the late Sen. Edward Kennedy when the Massachusetts Democrat was chairman of the Senate Judiciary Committee. That experience, Breyer said, made him a firm believer in compromise.

Still, he could write fierce dissents, as he did in the Bush v. Gore case that effectively decided the 2000 election in favor of Republican George W. Bush. Breyer unsuccessfully urged his colleagues to return the case to the Florida courts so they could create “a constitutionally proper contest” to decide the winner.

At the end of a trying term in June 2007 in which he found himself on the losing end of roughly two dozen 5-4 rulings, his frustrations bubbled over as he summarized his dissent from a decision that invalidated public school integration plans.

“It is not often that so few have so quickly changed so much,” Breyer said in a packed courtroom.

His time working in the Senate led to his appointment by President Jimmy Carter as a federal appeals court judge in Boston, and he served there for 14 years. His 87-9 high-court confirmation was the last with fewer than 10 dissenting Senate votes.

Breyer’s opinions were notable because they never contained footnotes. He was warned off such a writing device by Arthur Goldberg, the justice for whom Breyer clerked as a young lawyer.

“It is an important point to make if you believe, as I do, that the major function of an opinion is to explain to the audience of readers why it is that the court has reached that decision,” Breyer once said. “It’s not to prove that you’re right. You can’t prove that you're right; there is no such proof.”

Born in San Francisco, Breyer became an Eagle Scout as a teenager and began a stellar academic career at Stanford, graduating with highest honors. He attended Oxford, where he received first-class honors in philosophy, politics and economics.

Breyer then attended Harvard Law School, where he worked on the Law Review and graduated with highest honors.

He worked in the Justice Department’s antitrust division before splitting time as a Harvard law professor and a lawyer for the Senate Judiciary Committee.

Breyer and his wife, Joanna, a psychologist and daughter of the late British Conservative leader John Blakenham, have three children — daughters Chloe and Nell and a son, Michael — and six grandchildren.