“There was a scenario a week ago where you could have seen him walking out of here with a bag of delegates that would have made anyone say … ‘I don’t know how I can overcome that,” said Ace Smith, a top strategist on Kamala Harris’ presidential campaign who ran California for Hillary Clinton in 2008. “It’s looking increasingly like he’s not going to get that. If there are two people who emerge with more than 15 percent, it’s going to be a victory with a small ‘v.’”

The difference between a blowout victory for Sanders and a closer result in which one or two of his opponents cross the threshold to secure statewide delegates will prove immensely important to whether he racks up enough delegates around the country to put the race out of reach for anyone else.

Four years ago, Sanders lost California to Clinton on an emotional night for his campaign that came one day after media superdelegate-counters called the Democratic nomination for Clinton.

But he wasn't going to let that happen again this year. Sanders has established a long presence here that far surpasses his rivals, deploying hundreds of organizers and thousands of volunteers to the far corners of the state. He lent his outsize name to progressive candidates and causes. His advisers view their aggressive outreach to Latinos and independents as a major boon for their bid.

Sanders’ rivals, intent on pushing the race toward a contested convention, are trying to slash into his edge in California — but also in Texas and across the South and Northeast. Biden is counting on the consolidation of moderates from his big win Saturday, and favorable data showing that many Californians have hung on to their vote-by-mail ballots, to see how the race shakes out.

Complicating the calculus, a super PAC for Elizabeth Warren is spending in major media markets to boost her vote in congressional districts and statewide. And Mike Bloomberg, the billionaire self-funder making his primary debut, has spent more than $120 million on TV and digital ads across California and Texas.

Sanders has long viewed California as a welcoming state for him based on its demographics and politics. Ben Tulchin, Sanders’ San Francisco-based pollster, said the campaign early last year began to see his potential with Latino voters if they were able to communicate his core message of being the son of an immigrant who came to the U.S. for a better opportunity and spending much of his life trying to take on a rigged economy propped up by a corrupt political system.

“We found that economic message particularly resonated with Latinos and we saw in Nevada that play out very well,” Tulchin said.

Sanders’ considerable advantages here follow years of intense focus: He has been eyeing California’s massive delegate share — 415 pledged delegates, plus 79 superdelegates — since he lost the state to Clinton by 6 percentage points, with more than 360,000 votes separating them.

For Sanders’ supporters, there is added motivation in pushing him over the top this time. Less than 24 hours before the June 2016 primary, The Associated Press called the nomination for Clinton based on a survey of superdelegates, rendering the votes of more than 2 million Sanders backers functionally meaningless.

“Now, it’s almost like he had a bad date in 2016 and he’s back,” said Paul Mitchell, vice president of Political Data Inc. in Sacramento, who is tracking ballot returns in real time. “He’s brought the roses, he’s done his hair and brushed his teeth and now he’s ready to go. He’s been given a second chance to make an impression.”

At weekend rallies in San Jose and Los Angeles, Sanders nodded to California’s importance to his campaign while aides urged the nearly 25,000 attendees to follow state election rules that allow independent voters to request — and cast — a ballot in the Democratic primary. Sanders’ campaign has spent unprecedented time and money courting independents, running digital ads, sending thousands of calls, texts and customized mailers and putting the candidate out as part of a string of news conferences to familiarize them with the rules.

"NPP & INDEPENDENTS,” one ad on Spotify reads, "REQUEST YOUR PRESIDENTIAL PRIMARY BALLOT.” A mailer from the Sanders campaign spells out the specific process, step by step, to request a Democratic presidential ballot and includes the vote-by-mail ballot application itself.

Chuck Rocha, a senior Sanders adviser and architect of his Latino outreach effort, refers to the play as his “secret strategy to win California by a big number.” “There are 6 million [no-party preference] voters. Three million are going to get a ballot in the mail that does not include the presidential ballot,” Rocha explained in an interview. “And these people are overwhelmingly Latino and young. Guess who young Latinos love?”

Rocha said he targeted so-called NPP voters by calling them and literally patching them though to their county election officials to request a ballot in real time. It’s a process Rocha has used before to help put constituent pressure on members of Congress on policy issues — but never on the Sanders campaign. “We used that technology, which is something nobody has done before.”