Liberal US Supreme Court Justice Stephen Breyer will retire later this year after nearly three decades on the bench.

His decision ensures President Joe Biden will have an opportunity to nominate a successor who could serve for decades. But Justice Breyer’s replacement will not shift the court’s current 6-3 conservative majority. It comes as the court considers several hot-button issues.

Justice Breyer is expected to retire at the end of the current Supreme Court term in June. The court plays a key role in American life and is often the final word on highly contentious laws, disputes between states and the federal government, and final appeals to stay executions.

Each of the nine judges – known as justices – serves a lifetime appointment after being nominated by the president and approved by the Senate. Democrats have been pressuring Justice Breyer – who, at 83, is the oldest member of the bench – to retire so they can fill the seat with someone younger while they control the White House and Senate.

The last Supreme Court vacancy came in 2020, when liberal Justice Ruth Bader Ginsburg died at age 87. Former President Donald Trump was able to appoint her successor, Justice Amy Coney Barrett, less than two months before the US presidential election. Progressives like New York congresswoman Alexandria Ocasio-Cortez publicly called for Justice Breyer to step down. A van hired by the group Demand Justice and carrying the words “Breyer Retire” has also been seen driving around Washington.

According to multiple sources, Mr Breyer was “upset” over the leaked news because he “was not planning to announce his retirement today”. Mr Biden has previously pledged to nominate a black woman to the court for the first time if a vacancy opens. Only two African Americans – both men – have ever served on the court: Justice Thurgood Marshall from 1967 to 1991 and his successor Justice Clarence Thomas, who now becomes the oldest member on the bench at age 73.

A San Francisco native and Harvard Law graduate, Justice Breyer was appointed to his position in 1994 by President Bill Clinton. Over 27 years, he wrote more than 500 opinions and was among the high court’s most consistent liberal voices, delivering notable rulings on topics like gay marriage, healthcare, voting rights and the death penalty.

Known for his collegiality and prolific penmanship, he has expressed concern in recent years over the increasing politicisation of the court, telling an audience in 2021 that “it is wrong to think of the court as another political institution”.

In 1967, Justice Breyer married Joanna Hare, the daughter of John Hugh Hare, a former chairman of the British Conservative Party and the First Viscount of Blakenham. The couple both attended Oxford University as undergraduates.