OXNARD, Calif. — Kevin de León is one of the most prominent Democratic figures in the nation’s most Democratic state. He has drawn national attention from the Democratic left for a spirited challenge to Senator Dianne Feinstein and for the aggressive legislative challenges to President Trump’s policies advanced by the State Senate under his leadership.
But these days, Mr. de León is struggling for a toehold as he tries to negotiate the fraught and complicated terrain of trying to topple someone widely seen as a California institution. At 84, Ms. Feinstein is a five-term senator who began her political career as a member of the San Francisco board of supervisors in 1969, when Mr. de León was just 4 years old.
Mr. de León, 51, represents what many party members see as one of the leading faces of the next generation of California Democratic leadership amid calls for Ms. Feinstein to step aside to make room for the next class of leaders.
But Mr. de León’s struggles suggest that this moment of transition remains a work in progress. He would seem to have the right political makeup to lead the party to its next chapter. He is more liberal than Ms. Feinstein at a time when the left is on the rise. He is Latino in a state where the power of Latino voters continues to grow. And he is coming off almost four years as president of the Senate, giving him a platform to present himself as one of the state’s most aggressive leaders in opposing Mr. Trump.
Yet he is running against a powerful remnant of California’s old guard who enjoys strong historical, cultural and sentimental ties to many Democrats who have followed Ms. Feinstein’s career over the decades. Mr. de León’s run is exposing the challenges for a candidate who at any other time — or against another opponent — would seem to be a potentially powerful competitor.
Mr. de León is not, for the most part, facing questions on his record; rather, in the view of many of Ms. Feinstein’s supporters, she is a highly successful senator and foil to Mr. Trump, especially on national security issues, and there is simply no reason for her to go.
Ms. Feinstein’s hometown paper, The San Francisco Chronicle, in endorsing her, referred to Mr. de León as “the Young Turk.” In many ways, Mr. de León — who was blocked from seeking re-election to the Senate because of term limits — may end up being the right person but at the wrong time.
“I am not delusional,” he said over an açaí bowl at a diner in San Diego. “Listen, I am not naïve to the fact that people are not shouting my name all over the state of California. What we’ve identified is after 25 years of unchallenged incumbency, people in California want a change. And a new voice representing them. I want to be that voice.”
But he said, “It’s a tough race.”
Mr. de León did have a moment of triumph, as it were, a few months ago when he drew 54 percent of the delegate vote at the state Democratic convention in San Diego. That was enough to block Ms. Feinstein from winning the party’s endorsement (she drew 37 percent) but shy of the 60 percent needed to secure it for himself.
Polls, while of questionable accuracy given the mostly unknown field of candidates from both parties, suggest Mr. de León is struggling to win one of the top two spots in the June 5 nonpartisan primary. Ms. Feinstein has $10.4 million in the bank, including $5 million she lent her campaign, compared with $672,000 for Mr. de León, as of March 31.
So it was that Mr. de León could be found one recent Saturday driving himself around in his blue Chevy Volt from rally to picnic, singing along to Morrissey on the radio, in a one-car campaign caravan that took him from downtown Los Angeles to Thousand Oaks to Oxnard.
Mr. de León has earned applause from some Democrats for leading the Senate as it challenged Mr. Trump.
But Mr. de León’s tenure was also marked by a flood of sexual harassment cases involving lawmakers and legislative aides. Nearly 200 women signed a letter complaining of rampant sexual misconduct in Sacramento, and the disclosures forced Mr. de León and other legislative leaders to revamp disciplinary procedures.
He has hammered Ms. Feinstein for showing a willingness to work with Mr. Trump and he has taken positions on issues — military intervention, health care, tax cuts, among them — that stand in contrast to the more moderate and measured senator.
More pointedly, he made a point of contrasting his background with Ms. Feinstein, portraying her as the wealthy doyenne of San Francisco Democratic politics and himself as the working-class son of a San Diego barrio seeking to become this state’s first Latino senator. Mr. de León recently took a reporter on a tour of Logan Heights, the San Diego neighborhood where he grew up, and lingered at a single-room apartment where he shared a bed with his single mother who worked as a housekeeper. The tour was memorialized by an aide for a Facebook Live feed.