Sen. Dianne Feinstein, the Senate’s oldest member and longest-serving female, has died at 90, creating a political challenge for Democratic Gov. Gavin Newsom, who must appoint a replacement.

Feinstein’s office confirmed her death on Friday, The Washington Post reports. She died at her home in Washington, but no cause of death was stated. In May, her office revealed that the late senator suffered broader health complications than was previously known.

The California Democrat had announced plans to retire when her term ends in 2024, but her death forces Newsom, who vowed in 2021 to select a Black woman if her seat became suddenly vacant, to appoint a replacement right away.

Meanwhile, several Democratic candidates have been campaigning for the party’s nomination to replace Feinstein – including U.S. Rep. Barbara Lee, the only Black woman in the primary race.

Lee lashed out at Newsom after he reaffirmed his pledge earlier this month to appoint a Black woman on an interim basis to fill an early vacancy and ruled out any of the candidates to avoid tipping the scales.

"The idea that a Black woman should be appointed only as a caretaker to simply check a box is insulting to countless Black women across this country who have carried the Democratic Party to victory election after election," Lee said, according to CBS News, adding that there are no Black women currently serving in the Senate.

“If the governor intends to keep his promise and appoint a Black woman to the Senate, the people of California deserve the best possible person for that job. Not a token appointment. Black women deserve more than a participation trophy. We need a seat at the table."

Two years ago, when Newsom made his original pledge, many expected the governor to appoint Lee if Feinstein had agreed to resign amid concerns about her failing health, according to NBC News.

But that was before any candidates announced their primary campaign for her seat. Today, Lee is in a challenging race against high-profile Democratic rivals Reps. Adam Schiff and Katie Porter.

A poll released Sept. 7 placed Schiff in the lead with 20 percent of the likely vote, followed closely by Porter with 17 percent and Lee with a distant 7 percent.

Newsom is pressured to name a replacement soon as Congress fights over a spending bill to avert a government shutdown. However, the timing of Feinstein’s death adds some complications. Politico reports that the California secretary of states; staff met early Friday (Sept. 29) to determine the timelines that would govern an appointment or a possible special election.

Several Black women are considered possible appointees: California Secretary of State Shirley Weber, San Francisco Mayor London Breed, Los Angeles County Supervisor Holly Mitchell, and non-profit executive Lateefah Simon, currently running for Lee’s House seat.

When Vice President Kamala Harris stepped down from the Senate to become vice president, Newsom yielded to pressure from his Latino supporters and appointed then-Secretary of State Alex Padilla. Newsom vowed to appoint a Black woman if Feinstein resigned early was viewed as a move to make up for not choosing a Black woman to replace Harris.