Updated at 1:10 p.m. ET

Aversion of this storywas originally posted by member station KQED.

Before U.S. Sen. Dianne Feinstein could finish her speech at the California Democratic Party convention Saturday, the music began playing to indicate she had used her allotted time.

She kept talking. The music got louder. "I guess my time is up," Feinstein conceded as what sounded like a 1940s movie score continued playing.

Without missing a beat, supporters of her opponent, state Sen. Kevin de León echoed her statement in a chant: "Your time is up! Your time is up!" — a not-so-subtle reference to Feinstein's 25 years in the U.S. Senate.

It was a sign of things to come. The grass-roots Democratic activists gathered at the party's annual convention in San Diego this weekend implicitly rebuked the state's senior U.S. senator by denying her the party's endorsement for her re-election bid.

Feinstein finished far behind de León, the top Democrat in the state Senate. De León received 54 percent of delegates' votes to just 37 percent for Feinstein. It takes 60 percent to receive an endorsement.

While the lack of an endorsement certainly won't keep Feinstein off the ballot, it's a sign that grass-roots Democrats are eager to supplant leaders who are seen as too moderate and willing to compromise.

Democratic Party activists have never really been Feinstein's people. In 1990, when she was running for governor, she came to the party convention and expressed her support for the death penalty, eliciting boos from the liberal crowd. She lost the party endorsement to John Van de Kamp but got the nomination anyway, ultimately losing the November election to Pete Wilson.

Feinstein has always been a little to the right of where the party's activists are. Now, at age 84 and in her final campaign, Feinstein is once again at odds with progressives, despite her efforts to move left by more strongly opposing President Trump's agenda.

She said the Senate Appropriations Committee, which she sits on, would never approve $25 billion for Trump's wall along the Mexico border. But minutes later, de León's team sent texts noting that Feinstein had just voted for exactly that as part of the "Common Sense Coalition" immigration plan that failed to get through the Senate.

The bill would not only have provided a path to citizenship for so-called Dreamers, people in the U.S. illegally who were brought here as children, but it also included $25 billion for the wall.

Feinstein also reminded the crowd of her longstanding leadership on gun control, including her success against long odds at getting an assault weapons ban signed into law in 1994.

In his speech to the convention, de León reminded the crowd that his opponent hasn't always been a reliable liberal. "Democrats, you'll never have to guess where I stand," de León said before noting that he has championed issues such as raising the minimum wage, single-payer health care and the environment.

"Moral clarity is always doing the right thing when no one is watching," he said. "And it should never take a primary challenge to stand up for California values."

As leader of the state Senate, De León has had his own problems of late, most notably criticism of his slow response to the sexual harassment scandal in Sacramento. And while an endorsement from the Democratic Party would have provided a boost, his campaign is also overshadowed by Feinstein's huge advantages in name recognition and campaign cash. A recent poll from the Public Policy Institute of California had her leading de León by 46 percent to 17 percent.

Despite the boost for De León, the vote is in some ways a loss for him. Democratic campaign strategist Katie Merrill says he needed the endorsement much more than Feinstein.

"He was such a narrow path to the Senate, and he had to have this Democratic Party endorsement," she said. "This was the one strategic thing he need to accomplish here and he did not accomplish it."

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