Adam Schiff, the California congressman who became a household name as the lead prosecutor in Donald Trump’s first impeachment, said he will seek the California Senate seat currently held by Dianne Feinstein.

“I wish I could say the threat of Maga extremists is over,” said Schiff, 62, in a video announcing his campaign. “We’re in the fight of our lives – a fight I’m ready to lead as California’s next US senator”.

Schiff is joining fellow southern California Democrat Katie Porter in declaring his candidacy for the Senate seat before Feinstein has even announced her retirement. At 89, Feinstein is the oldest member of the Senate, and has told reporters this week that she will make a decision about 2024 in the “next couple of months” amid circling questions about her cognitive health.

Schiff, who is close with Feinstein, said he had spoken to her a day earlier to inform her of his intention to run.

“I want to make sure that everything I did was respectful of her and that I did so with her knowledge and her blessing,” Schiff told the Associated Press.

Many will be clambering for her seat. Bay Area representative Barbara Lee has reportedly told colleagues and donors that she plans to run, and political analysts expect Silicon Valley representative Ro Khanna could also mount a competitive campaign.

Schiff has proved to be a formidable fundraiser, with $20.6 m in campaign money at the end of November according to Federal Election Commission reports. His announcement comes after the House speaker, Kevin McCarthy, blocked Schiff from serving on the intelligence committee.

He has launched his campaign emphasizing his antagonizing of Trump and his allies. “If our democracy isn’t delivering for Americans, they’ll look for alternatives, like a dangerous demagogue who promises that he alone can fix it,” Schiff said.

“I think that record of leadership, that record of staunch defense of our democracy, and the way that I’ve championed an economy that works for everyone, I think are a powerful record to run on,” he said.

Schiff was first elected to Congress in 2000 and represents parts of Hollywood. Before that, he was a federal prosecutor and served in California’s state senate, where his tough on crime record has been criticized by criminal justice and immigrants rights advocates.

His record in Congress veers more centrist than that of Porter, Lee or Khanna.