"The only way we beat Trump is with the largest voter turnout in the history of this country," Sanders said. "And that is what our campaign is uniquely capable of doing."
Sanders spoke a day after former Vice President Joe Biden's victory in the South Carolina primary, and minutes before news broke of former South Bend Mayor Pete Buttigieg's departure from the race.
With a narrowing field of moderate Democrats standing in his path to the nomination, Sanders focused his attention on Biden, slamming his past votes in favor of the Northern American Free Trade Agreement and the Iraq War.
"Please do not forget Joe Biden voted for the war in Iraq," Sanders said. "And that was the worst political decision ever made by the United States Congress."
Sanders has maintained a strong lead in California primary polls, although those snapshots of the electorate were taken before Biden's victory in South Carolina and Buttigieg's departure from the race.
The latest Change Research poll commissioned by KQED last week found Sanders with the support of 37% of Democratic primary voters, followed by Massachusetts Sen. Elizabeth Warren at 20% and Biden at 12%.
The excitement among Sanders supporters in San Jose over a potentially decisive win in California was palpable. Many supported his presidential run four years ago, and have backed progressive causes even longer.
"I'm 85 years old and I've been fighting for the rights of people all my life," said Uvaldo Palomares of Livermore. "This is as close as we've gotten."
Sunnyvale resident Bryan Allata said he was confident about Sanders' chances on Tuesday.
"He wasn't able to break through in 2016, but you can kind of feel that the dam is breaking," Allata remarked.