NBC News has confirmed that Associate Justice Stephen Breyer will retire at the end of this term, paving the way for President Joe Biden to name his successor.

Breyer, 83, is the court’s oldest member. He has served for 27 years on the court, and had given few indications that he was seriously considering stepping down. In interviews last summer, after publication of his book about the high court and how it should not been seen as a partisan institution, the likelihood of his stepping aside seemed slim. It could be that the court’s extremist majority and its recent actions have convinced him otherwise.

Most recently, the court decided to take up an affirmative action challenge that would overturn previous precedent. In the Trump court, the promises of Brett Kavanaugh and Amy Coney Barrett that cases like this one—with “precedent on precedent”—could not be casually overturned have proven empty.

The court even decided to expedite the University of North Carolina case, which hadn’t yet been taken up by an appeals court. That’s another feature of that new conservative-dominated court, which has granted 15 cases that hadn’t been yet heard by an appeals court since 2018. From 2004 through 2017, it granted zero such petitions.

Combined with using the shadow docket to decide some of the most controversial and extreme rulings with no public argument and no transparency, this Trump-packed court is looking more radical by the day.

Apparently the recent extreme partisanship of the court convinced the justice that it was too risky to leave to chance his continued good health. It’s also possible that he’s concerned that the efforts to expand and reform the court are gaining steam, and his departure could help allay concerns and slow that train down.

In his 2020 campaign President Joe Biden promised he would nominate a Black woman to the Supreme Court, were he to get the opportunity. The likeliest contenders are federal Judge Ketanji Brown Jackson and California Supreme Court Justice Leondra Kruger.