In summary The contrast between U.S. Sen. Dianne Feinstein and her challenger state Senate leader Kevin de León came into stark focus Friday night at the California Democratic Party convention.

California’s senior senator took the stage to polite but tepid applause. The Democrat challenging her for re-election stepped up to rousing chants of, “Ke-vin! Ke-vin!”

It was just a warm-up before tomorrow’s main event when delegates at the California Democratic Party will make their endorsement, but the contrast between U.S. Sen. Dianne Feinstein and state Senate leader Kevin de León came into stark focus Friday night as the candidates made brief pitches to the party’s labor caucus during its convention in San Diego.

Feinstein said little about workers’ issues and instead talked mostly about gun control, saying that mass shootings have become more common since her 1994 bill banning assault weapons expired in 2004. She introduced a new version of it in November following mass shootings at a Texas church and Las Vegas music concert.

“I have been a woman on a mission to ban assault weapons,” Feinstein said to applause.

But when de León took the mic, the room went wild, and the termed-out state legislator seemed to revel in the moment.

“Brothers and sisters, I am one of you,” said de León, who began his career as a teachers union organizer. He talked about his work on bills to raise the minimum wage in California and launch a retirement savings plan for private-sector workers, saying he had been working with unions “on the front lines, not on the side lines.”

Many Californians don’t know who de León is, and he trails Feinstein in the polls by almost 30 points. But he has been endorsed by powerful labor unions, including the Service Employees International Union and the California Nurses Association. So it was little surprise that the house of labor sent de León off the stage with chants of, “Sí se puede.”