SAN JOSE — Tampa Way here in east San Jose was concrete-solid Hillary Clinton country four years ago.

But Ivan Aguilar, 27, is trying to change that. The political science student took a months-long sabbatical to work the streets for Sen. Bernie Sanders (I-Vt.). On a recent warm Sunday, he knocked on doors of homes filled with families who commute an hour or so to five-figure jobs in Silicon Valley.

“When it comes to this kind of canvassing, it’s a numbers game,” Aguilar said, a list of registered Democrats in hand, along with placards and door hangers in English and Spanish. “You knock on 50 doors, and maybe you get 10 to 20 conversations. But a few can really matter.”

Aguilar’s organizing is part of a concerted, years-long effort by Sanders to gin up a decisive victory in California’s presidential primary. The state’s usually beside-the-point voters could play a key role in the Democratic nominating process this year. There are 415 delegates at stake here Tuesday, the largest haul on a day when 14 other states and territories will also go to the polls. Sanders is hoping that a big victory could help him run up a sizable delegate lead against his rivals.

The campaign has a state organization far larger than those of his opponents — 22 offices and more than 100 paid staffers. And it has been targeting Latinos, Asian Americans and young voters, key demographics in the Democratic electorate.

“The Sanders people looked at the primary with a long view and not just as a momentum play,” said Steven Maviglio, a Democratic political consultant who is not working for any candidate and said he has yet to decide whom he will choose in the primary.

“They actually invested in door-knocking, which if you notice some analysts talking about how to win California, they have really discounted that ground activity,” he said. “But this seems to have worked, and it appears to have poked awake the sleeping giant of the Latino vote.”

A Suffolk University/USA Today poll showed Sanders with a double-digit lead. He was at 35 percent among likely Democratic primary voters, well ahead of former New York mayor Mike Bloomberg at 16 percent, former vice president Joe Biden at 14 percent and Sen. Elizabeth Warren (D-Mass.) at 12 percent. The percentages matter because a candidate who fails to win 15 percent of the vote statewide receives no delegates.

A candidate must also reach the 15 percent threshold in a congressional district to win district delegates, which account for two-thirds of those allocated. Hitting that mark could be especially challenging this year because the Democratic field is unusually large.

It is harder to measure how Sanders is doing district by district, how well his democratic socialist message is playing in parts of Silicon Valley or wealthy, tax-averse Southern California counties. It’s hard, too, to know whether he’ll be able to turn out the broad, new coalition, something he has struggled to do in some early states.

Officials say they’re confident. “The campaign really prioritized California in a way that we hadn’t before,” said Rafael Návar, the Sanders campaign’s state director. “Most people looked at the first four states. I looked at it as five states, and so California had a prioritization from the start.”

One key rival for Sanders is Warren, who is hovering around the 15 percent vote threshold, according to some recent polls. Her campaign has about half as many staff members on the ground as Sanders.

“California’s a progressive state, and Elizabeth Warren is a progressive candidate,” said Kevin Liao, the campaign’s state spokesman. “She’s a good fit for the values of the state.”

Julián Castro, a former Obama Cabinet member who dropped out of the Democratic primary race earlier this year, recently appeared at a Warren event in San Francisco that drew about 150 staff members, volunteers and others.

It seems part of an effort to cut into Sanders’s lead among Latinos, especially older ones less liberal on issues of ethnic identity and more suspect of Sanders’s Medicare-for-all proposal. Several polls show Sanders drawing nearly half the state’s Latino support.

Warren plans to speak Monday, on the eve of the primary, in East Los Angeles to an audience of Latino building services workers.

Some of his better-funded rivals have also looked hopefully toward television. California is a place where intensive advertising usually proves essential in winning statewide races. But those rich enough to afford big buys in multiple markets are then often resented, especially the self-financed candidates.

In 1994, then-Rep. Michael Huffington spent more than $40 million of his family’s oil fortune in an unsuccessful bid to beat Sen. Dianne Feinstein (D-Calif.). Sixteen years later, Meg Whitman, the billionaire former eBay chief executive, invested $144 million of her own money in losing to Jerry Brown.

This year, two billionaires in the presidential race have been dominating the air. Bloomberg and investor Tom Steyer, who dropped out after a poor performance Saturday in the South Carolina primary, have been ubiquitous in recent weeks on California television, popular YouTube channels and other media. Warren plans a homestretch run of radio advertising, in part to save her resources for later.

But it’s not clear whether endorsements or heavy spending will dent Sanders’s lead, nor whether Biden’s surge in South Carolina will itself alter the trajectory of California.

Biden has spent little time in the state, traveling here more for fundraising than for organizing.

In east Santa Clara County and farther north, up through Alameda County, home of Oakland, Democrats outnumber Republicans by more than 5 to 1. The East Bay is highly diverse ethnically, and the Sanders team is looking for every one of those votes.

A recent day started for the campaign staff with Spanish-language outreach, door to door, then moved to a Black Forum on Economic Justice in a cathedral on the edge of Berkeley where the city’s former mayor Gus Newport represented the Sanders campaign before an almost entirely African American audience of about 150.

About 6 percent of the electorate is African American, a demographic Biden has targeted, especially in his successful campaign effort in South Carolina.

His campaign did not send a representative to the forum.

“I know this is the time when we start to see these campaigns and candidates pandering for African American votes,” said the forum’s co-host Patricia Brooks, a digital strategy consultant, looking out over the pews. “I see a lot of heads nodding out there. I mean, where do they go after they win?”

The day ended with a celebration at Sanders’s downtown Oakland headquarters, where about 60 or so Iranian Americans gathered to endorse the campaign.

Both Alameda and Santa Clara County went for Clinton four years ago, and Aguilar is door-knocking to find out how Sanders might take her place this time.

His pitch in Spanish is basic. Start with the day of the vote, ask whether they have heard of Sanders, then come with the substance: Medicare-for-all, an end to college debt, a push for more affordable housing, tax reform to close the gap between those with and the many without.

These are California issues, as well as the nation’s. He doesn’t mention other candidates.

“More than anything, it’s the issue of income inequality that resonates most,” Aguilar said. “It’s more like an umbrella term that covers health insurance, the rich paying too little in taxes. Income inequality captures all of it, and it’s the one thing people really want to talk about.”

Aguilar leaves bilingual door hangers at the first few homes, where nobody was there. “Nuestro Futuro,” the brochure reads, facing out with a photo of the smiling senator.

At 1924 Tampa Way, Francisco Escorcia opens the grated front door. He is registered to vote, and when Aguilar starts talking about college affordability, Escorcia, who builds gas stations for a living, lights up. He has three children — ages 7, 14 and 21 — and school costs are a major worry.

Escorcia is 47, at the very upper edge of the typical young Latino Sanders supporter. He chose Clinton last time, but he says, “I really do like what you are saying now.”

Aguilar marks him down as a strong likely supporter.

A few houses down, Gonzalo Burgara, who is 46 and works in construction, listens to Aguilar’s pitch. He is not a citizen, only a resident, and cannot vote. But his 18-year-old son can, and Aguilar offers to drive him to the voter registration center once he gets home.

Burgara agrees to send along his son. Ten minutes later, as Aguilar passes Burgara’s green work truck, he sees that the newly acquired “Bernie” sticker is already on the bumper.

“That’s what I like to see,” Aguilar said.

Among the last houses Aguilar visited on Tampa Way highlighted what 57 percent of Californians voters say is among their top concerns: Beating President Trump in November and which Democratic candidate can do it.

“I just want him out,” said Odette Santos, 42, who works as a medical assistant at the Stanford Medical Center, which is a long commute.

Aguilar has some answers: the legion of Sanders volunteers, the logic that an energized Trump base can only be challenged by an energized Democratic base. And Sanders, he said, is the one who brings that energy.

Santos is not sure. But she tells Aguilar she will consider it.

Disappointed, Aguilar marks her as undecided as he makes his way back to the gray Honda Civic and another neighborhood on his long list.