California Gov. Gavin Newsom will appoint Laphonza Butler, the president of EMILY’s List, to fill the late Democratic Sen. Dianne Feinstein’s Senate seat, his office confirmed Sunday evening.

Butler will become the sole Black female senator serving in Congress and only the third in US history. Feinstein, the longest-serving female US senator in history, died last week at 90.

The selection of Butler, first reported by Politico, comes as Democrats hold a narrow Senate majority and uncertainty looms over New Jersey Sen. Bob Menendez’s political future amid outcry from his Democratic colleagues over his federal indictment.

Butler has been the president of EMILY’s List, which works to elect Democratic women who support abortion rights, since the group’s board of directors appointed her in 2021, when she became the first woman of color to lead the organization. She previously worked at Airbnb as a director of public policy and campaigns and advised Vice President Kamala Harris’ 2020 presidential campaign, but much of her background is in the labor movement, serving as a union president in California.