California Gov. Gavin Newsom (D) announced the appointment of Laphonza Butler to the U.S. Senate, following the passing of Sen. Dianne Feinstein (D-California), who held the seat for more than 30 years.

Butler is the president of EMILY’s List, the nation’s largest organization dedicated to electing women to public office. She will serve out the remainder of Feinstein’s term, which runs through 2024.

“An advocate for women and girls, a second-generation fighter for working people, and a trusted adviser to Vice President Harris, Laphonza Butler represents the best of California, and she’ll represent us proudly in the United States Senate,” Newsom said in a news release on Sunday.

“As we mourn the enormous loss of Senator Feinstein, the very freedoms she fought for — reproductive freedom, equal protection, and safety from gun violence — have never been under greater assault,” Newsom continued. “Laphonza will carry the baton left by Senator Feinstein, continue to break glass ceilings, and fight for all Californians in Washington D.C.”

Feinstein passed away on September 29, at the age of 90. She was the first woman to represent California in the Senate, where she later became the first woman to hold leadership roles on powerful legislative committees in the chamber.

“Sen. Dianne Feinstein was a titan of the Senate and a legendary figure for women in politics. Entering leadership in crisis, she would go on to repeatedly shatter glass ceilings in a lifetime of service,” Butler said in an EMILY’s List release on September 29. “She was the first woman to be president of the San Francisco Board of Supervisors, the first woman to be mayor of San Francisco, the first woman to serve as U.S. senator from California, the first woman to chair the Senate Rules and Intelligence committees, and the first woman to preside over a presidential inauguration.

“Her legacy of groundbreaking leadership is matched by a deep and lasting record of policy achievement,” Butler added. “Sen. Feinstein wielded tough government oversight to advance consumer protections and human rights, LGBTQ+ equality, and environmental protections.”

California is home to more than 100 tribes and the largest population of American Indians and Alaska Natives in the U.S. In recent years, Feinstein advocated for a Native youth treatment center, the first Native federal judge in the state, improved protections for Native women in the Violence Against Women Act and for urban Indian health providers.

Feinstein also raised eyebrows for her views on Indian gaming, one of the largest markets in the nation. Through proposed legislation, she tried to hinder the restoration of tribal homelands and to stop new casinos in California.

Butler is the second African American woman to represent California in the Senate. The first was Kamala Harris, who now serves as vice president of the United States.

Butler could be sworn into office as soon as this week. She will join Sen. Alex Padilla (D-California) as California’s members in the Senate, where Democrats hold a narrow but significant majority in the chamber.

“Throughout her career, Laphonza Butler has been a strong voice for working families, LGBTQ rights, and a champion for increasing women’s representation in politics,” Padilla said in a statement on Sunday. “I’m honored to welcome her to the United States Senate.

“Governor Newsom’s swift action ensures that Californians maintain full representation in the Senate as we navigate a narrow Democratic majority,” Padilla said. “I look forward to working together to deliver for the people of California.”

Padilla himself was appointed to the Senate following the rise of Harris to the White House. He later went on to win an election to serve a full term in the chamber.

The election to choose a full-term successor for Feinstein takes place in November 2024. More than a dozen candidates, including three Democrats in the U.S. House of Representatives, have declared they are running.