White House chief of staff Ron Klain, who has spent more than two years as President Joe Biden’s top aide, is preparing to leave his job in the coming weeks, according to a person familiar with Klain’s plans.

Klain’s expected departure comes not long after the White House and Democrats had a better-than-expected showing in the November elections, buoyed by a series of major legislative accomplishments, including a bipartisan infrastructure bill and a sweeping climate, health care and tax package that all Republicans rejected.

The personnel change is also a rarity for an administration that has had minimal turnover so far. No member of Biden’s Cabinet has stepped down, in stark contrast to Donald Trump’s White House, with frequent staff turmoil and other crises.

The person familiar with Klain’s plans was not authorized to discuss the matter publicly and spoke on condition of anonymity to confirm the development, which was first reported by the New York Times.

The White House did not return calls or emails seeking comment on Klain’s expected exit.

Now that Republicans have regained a majority in the House, the White House is preparing to shift to a more defensive posture. GOP lawmakers are planning multiple investigations into the Biden administration, examining everything from the chaotic U.S. withdrawal from Afghanistan to U.S. border policy. Republicans are are pledging to investigate the president’s son, Hunter Biden.

Klain’s departure also comes as the White House struggles to contain the fallout after classified documents dating from Biden’s time as vice president were discovered at his home in Wilmington, Delaware, and at his former institute in Washington. Attorney General Merrick Garland has appointed a special counsel to investigate the matter.

Among those on the shortlist to succeed Klain include Steve Richetti, counselor to the president; Labor Secretary Marty Walsh; former White House COVID-19 response coordinator Jeff Zients; Agriculture Secretary Tom Vilsack; and Anita Dunn, a White House senior adviser.

Dunn, who has publicly ruled out interest in the chief of staff job, but would be the first woman in the post. She played a leading role in shaping Biden’s political and communications strategy, including the “ultra-MAGA” framing of Republicans that helped Democrats exceed expectations during the 2022 midterms.

Zients has returned to the White House since running the COVID-19 response team in a low-profile role to ensure the administration is appropriately staffed for the remainder of Biden’s first term. Richetti, a former lobbyist, followed after Klain and senior adviser Bruce Reed as Biden’s final vice presidential chief of staff.

Walsh, Boston’s mayor before joining the Cabinet, earned praise from Biden as recently as Friday for his job performance. Vilsack, a former Iowa governor, is in his second stint as agriculture secretary after serving in the role for the entirety of the Obama administration. He volunteered for Biden during Biden’s ill-fated 1988 presidential bid in Iowa.

Klain, a longtime Democratic political operative, has overseen a West Wing that has been largely free of the high-stakes drama that permeated the upper echelons of the Trump administration. Klain has been an outspoken proponent of Biden’s agenda via Twitter, where he frequently engages with reporters to defend the president’s record.

The Indianapolis native has served under Biden for decades, including as chief counsel of the Senate Judiciary Committee when Biden was its chairman. Klain also worked on judicial picks in the Clinton White House, helping with the nomination of Ruth Bader Ginsberg for the Supreme Court.

“With all due respect to my predecessors, I’m sure this is a higher priority for me.” Klain said in an Associated Press interview last month in which he discussed the importance placed byr Biden of seating judges on the federal bench. ”The fact that (the president) makes it such a priority, makes it a big priority for me.”