The race for California's coveted Senate seat has kicked off, and it's shaping up to be an expensive, ugly battle between two of the top political fundraisers in the House chamber. 

Rep. Adam Schiff, D-Calif., who announced his bid for the Senate seat on Thursday, joins Rep. Katie Porter, D-Calif., in a competitive race for the seat held by Sen. Diane Feinstein, 89, who is up for re-election in 2024. Feinstein has not yet announced re-election intentions.

Porter, a progressive rising star and former pupil of Democratic Sen. Elizabeth Warren, raised a whopping $25 million in political donations last cycle, making her the second-highest-raising House member behind House Speaker Kevin McCarthy. Porter's fundraising total even beat out that of her boss, then-House Speaker Nancy Pelosi — a renowned fundraiser in her own right. 

Schiff was the fourth-highest-raising member of the House members up for re-election last year, taking in just over $23 million from 2021 through November 2022. 

CALIFORNIA DEMOCRAT REP. ADAM SCHIFF TO RUN FOR US SENATE SEAT HELD BY FEINSTEIN

Despite attempts to position herself as a progressive "warrior," Porter and her political ambitions may be impeded by accusations of racist remarks and promoting a toxic work culture.

An ex-staffer for the California Democrat alleged that the congresswoman had made rude and racist comments to staff and said that she had "ridiculed people for reporting sexual harassment." The accusations came to light in December, but the news was mostly ignored by major news outlets.

Schiff, a figurehead of the impeachment investigations into former President Donald Trump, faces his own share of intra-party backlash. A progressive group attacked the congressman for his record on Trump only hours after Schiff announced his run for U.S. Senate.

"Adam Schiff plays the role of Trump antagonist on TV, but a recent book details how he stalled and undermined leaders trying to hold Trump accountable in Congress. And he never challenges corporations or the Democratic establishment," Adam Green, co-founder of the Progressive Change Campaign Committee (PCCC), said Thursday in a statement. 

SCHIFF HIT WITH ETHICS COMPLAINT ONE DAY INTO SENATE CAMPAIGN FOR USING TRUMP IMPEACHMENT VIDEO

Not long after, an ethics watchdog group called on the Office of Congressional Ethics (OCE) to investigate Schiff for using footage from the Senate floor in his campaign announcement video. The Foundation for Accountability and Civic Trust (FACT) said the California progressive had "abused official resources for political purposes," according to its complaint filed Friday. 

California Congresswoman Barbara Lee, 76, has said she intends to run for Feinstein's seat as well, but she has not made an official announcement. 

Some have also speculated that Democratic Rep. Ro Khanna, representing California's Silicon Valley, may also throw his hat in the ring for Feinstein's seat. 

California uses a so-called jungle primary system in which the top two candidates in the primary advance to the general election, regardless of their party, making a Democrat-on-Democrat showdown in the 2024 general election highly possible.

Fox News' Houston Keene contributed to this report.