Hillary Clinton may have won the Democratic presidential nomination even before the polls close Tuesday in California, three time zones to the west of New Jersey.

So in terms of the decisive measurement - raw number of delegates won - California does not matter.

Except that it does, because California is not just any state: It's the nation's most diverse and a mainstay of the Democratic Party. Losing there to Vermont Sen. Bernie Sanders, an independent leftist who only joined the party to seek its nomination, would damage Clinton at the end of a brutal primary season just as she needs to unify Democrats for the battle against Donald Trump.

A California loss would highlight what has been a recurring weakness for Clinton's candidacy in the nominating contests: a lack of enthusiastic support from the party's liberal base and young voters.

In addition to California and New Jersey, New Mexico, Montana, and South Dakota will hold presidential primaries Tuesday, and North Dakota will have a Democratic caucus. New Jersey voters also will pick party nominees for the U.S. House.

California could be telling for the state of Trump's campaign, as well, even though he has clinched the GOP nomination.

When Mitt Romney went to California in 2012, the race was mostly uncontested, though former Texas Rep. Ron Paul was lingering. Romney, the eventual Republican nominee, won 78 percent of the vote, said Paul Mitchell, a Democratic political consultant in Sacramento who is vice president of the bipartisan data firm Political Data Inc.

"What does Trump get in a fully uncontested race?" Mitchell asked.

"We are seeing the first large stage upon which there is a Republican yay or nay vote on his ability to consolidate the party," he said, adding that California's electorate in some ways represents a "mishmash of different states" that's a microcosm of the country.

Clinton needs 70 delegates to clinch the nomination; 694 are up for grabs Tuesday.

Late last week, Clinton and her husband, former President Bill Clinton, dropped everything to flood the zone in California through the primary. They have scheduled more than 30 campaign events between them. The Clinton campaign has opened eight offices and is running phone banks in seven languages.

Sanders has been stumping exclusively in the Golden State for a couple of weeks, hoping for a decisive win that would help him peel away superdelegates who have committed to Clinton and build the case that he would be the better standard-bearer.

Team Clinton arrived with the most recent polls showing a race that is effectively tied, though the Real Clear Politics average of polls had the former secretary of state with a 6-point lead.

Meanwhile, the party's national convention in Philadelphia is less than two months away, and a Sanders victory could embolden him to push the nomination fight into July. (He has said the convention may be "messy," and the Sanders campaign is working to organize a massive protest rally across from the Wells Fargo Center in FDR Park.)

"This is no time for Democrats to keep fighting each other," California Gov. Jerry Brown said last week in endorsing Clinton. "The general election has already begun."

Brown has been a hero to many progressives in his long career and is not a Clinton family friend. Indeed, he was the liberal insurgent who battled Bill Clinton throughout the 1992 primaries.

Sanders, who says he will have directly reached more than 250,000 Californians at his rallies by Tuesday, also has indicated the state represents his last, best chance to get the nomination.

"I'm knocking my brains out to win the Democratic nomination," Sanders said May 29 on NBC's Meet the Press. "California is the big enchilada. Obviously if we don't do well in California, it will make our path much, much harder."

It is difficult to dominate a Democratic primary contest because the party awards delegates proportionally based on popular votes statewide, and in some cases by congressional district as well.

About one in nine Americans live in California, and the state is majority-minority, with Latinos making up about 40 percent of the population.

Voters who are not registered with a party can request a ballot at a polling place, a step that has been confusing to some. Voting also has been underway for weeks by mail, making it harder to predict trends. Sanders has performed better in states where independents can participate in Democratic primaries, and California polls show that he has more support among this group than among registered Democrats.

Mitchell, the Sacramento-based data consultant, said California primary voters appear to be engaging the election in "record numbers."

Voter registration in the state has surged even more than it did during the 2008 general election victory for Barack Obama, which set the prior record, Mitchell said.

There also has been "significant growth in early voting in the state," showing signs of a "very competitive race," he said.

Bob Mulholland, a California superdelegate who backs Clinton, said Clinton's lead among voters older than 40 and registered Democrats who vote in primaries gives her an edge Tuesday.

"Donald Trump is our best organizing tool," he said.

Even if Sanders were to win the state, Mulholland does not think Clinton's campaign, or party unity, would be damaged.

"It's a one-day story if that happens," he said. "People forget that in '08 then-Sen. Clinton won eight of the last 11 primaries. We went to the Denver convention, and nobody was talking about that. Obama was the nominee, and the party united around him."

tfitzgerald@phillynews.com

215-854-2718@tomfitzgerald

www.philly.com/bigtent

New Jersey Primary

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Voters in New Jersey will pick party nominees Tuesday for president, U.S. House of Representatives, and county and local offices.

Polls will be open from 6 a.m. to 8 p.m.

In congressional races, First District incumbent Rep. Donald Norcross of Camden is being challenged by Alex Law of Voorhees in the Democratic race. Republican Bob Patterson of Haddonfield is unopposed.

In the Shore counties' Second District, Democrats David Cole of Sewell and Costantino Rozzo of Vineland are competing to face Republican Rep. Frank LoBiondo in the fall.

Loan officer Frederick Lavergne of Delanco and former Asbury Park councilman Jim Keady are fighting for the Third District Democratic nomination to run against incumbent Rep. Tom MacArthur.EndText

INSIDE

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Trump's attacks on judge spark concerns. A17.

Could Clinton clinch Sunday? It's possible. A17.

Clinton outlines dangers of Trump foreign policy. C1.

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