California Gov. Gavin Newsom will name Laphonza Butler, a Democratic strategist and adviser to Kamala Harris’ presidential campaign, to fill the vacant U.S. Senate seat held by the late Sen. Dianne Feinstein, a spokesman in his office said Sunday.

In choosing Butler, Newsom fulfilled his pledge to appoint a Black woman if Feinstein’s seat should become open. However, he had been facing pressure by some Black politicians and advocacy groups to select Rep. Barbara Lee, a prominent Black congresswoman who is already running for the seat.

The long-serving Democratic senator died last Thursday after a series of illnesses. Butler leads EMILY’s List, a political organization that supports Democratic women candidates who favor abortion rights. She also is a former labor leader with Service Employees International Union 2015, a powerful force in California politics.

Butler currently lives in Maryland, according to her EMILY's List biography.

She did not immediately respond to a request for comment. A spokesman in Newsom's office who declined to be named confirmed to the Associated Press that Newsom had chosen Butler.

Democrats control the Senate 51-49, though Feinstein’s seat is vacant. A quick appointment by Newsom will give the Democratic caucus more wiggle room on close votes, including nominations that Republicans uniformly oppose. She could be sworn in as early as Tuesday evening when the Senate returns to session.

Feinstein, the oldest member of Congress and the longest-serving woman in the Senate, died at age 90 after a series of illnesses. She said in February she was would not seek reelection in 2024. Lee is one of several prominent Democrats competing for the seat, including Democratic U.S. Reps. Katie Porter and Adam Schiff. Newsom said he did not want to appoint any of the candidates because it would give them an unfair advantage in the race.

His spokesman Anthony York said the governor did not ask Butler to commit to staying out of the race. Dec. 8 is the deadline for candidates to file for the office.

Butler has never held elected office but has a long track record in California politics. She served as a senior adviser to Harris's 2020 presidential campaign while working at a political firm filled with strategists who have worked for Newsom and many other prominent state Democrats. She also briefly worked in the private sector for Airbnb.

She called Feinstein “a legendary figure for women in politics and around the country,” in a statement posted after Feinstein's death.

EMILY's List, the group Butler leads, focuses on electing Democratic women who support abortion rights. With the U.S. Supreme Court's 2022 decision to overturn women's constitutional right to abortion, the issue has become a galvanizing one for many Democrats.

It’s not Newsom’s first time selecting a U.S. senator, after being tasked with choosing a replacement for Kamala Harris when she was elected vice president; at that time, he selected California Secretary of State Alex Padilla for the post. It was one of a string of appointments Newsom made in late 2020 and early 2021, a power that gave him kingmaker status among the state’s ambitious Democrats.

The seat is expected to stay in Democratic hands in the 2024 election. Democrats in the liberal-leaning state have not lost a statewide election since 2006, and the party holds a nearly 2-to-1 voter registration advantage over Republicans.