WASHINGTON — As she moves swiftly to build a juggernaut in her home state, California Sen. Kamala Harris is revealing what looks like an audacious strategy for delivering a mortal blow to her rivals for the Democratic presidential nomination next March.

It relies on her geographical edge at home, her perceived demographic advantage in the South and a primary calendar that brings them together on March 3 — known as "Super Tuesday" because it is the date on which the most delegates to the party's convention are in play in primaries across the country.

California voters alone will send more than 400 delegates to the convention, nearly double second-ranking Texas, and Harris, who is one of two African-American candidates in the race, is likely to have a shot at consolidating the black electorates in Southern states voting on Super Tuesday, including Alabama, Tennessee, North Carolina and Virginia.

In 2008 and 2016, respectively, Barack Obama and Hillary Clinton fueled their nominations with massive delegate hauls in heavily African-American Southern states where black voters formed a bloc behind the winning candidate. Harris would like to repeat those feats — a bigger challenge, for sure, in a multi-candidate race that also features Sen. Cory Booker, D-N.J., who is black.

But for Harris, the real key is to make California — where it is notoriously expensive and difficult to organize statewide campaigns — a maelstrom of wasted time and money for everyone else. And while she's been making the rounds of early states with the other Democrats, her campaign has begun the work of standing up an operation back home.

"You need a long runway to build and run here," said Buffy Wicks, a state House member who ran Obama and Clinton's winning primary campaigns in California. Wicks is something of a secret weapon for Harris: an elected official who has endorsed the senator but also brings to the campaign unrivaled experience in winning contested presidential primaries in the state.

Harris already has enlisted three-quarters of the Democrats in the state Senate — whose districts are larger than those of U.S. House members — and campaign co-chairs Gov. Gavin Newsom, Rep. Barbara Lee, D-Calif., and Dolores Huerta, an iconic labor leader.

And while endorsements only carry so much weight, each of those three come equipped with deep ties to various elements of the state's donor and activist bases, including African-Americans, Latinos, progressives and organized labor. That could come in handy in a state with unique organizational challenges for presidential candidates, who have to run statewide campaigns across the country simultaneously.

In smaller states, Wicks said, campaigns typically rely on paid staff to build their operations. California is too big for that. Instead, she said, the trick is to turn to a "lay leadership" network of existing activists to help organize the state, many of whom have worked to elect Harris as attorney general and senator.

It's not unusual for a presidential candidate to lock down support in his or her backyard first. Sen. Bernie Sanders has the endorsements of Sen. Patrick Leahy and Rep. Peter Welch — his only two colleagues in Vermont's congressional delegation — Sen. Elizabeth Warren, D-Mass., scored a coup with the sought-after endorsement of fellow Massachusetts Democrat Rep. Joe Kennedy, and Sen. Cory Booker, D-N.J., announced his local presence with authority in rolling out a complete set of 13 endorsements from the Garden State congressional delegation on Thursday.

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But California, because of its size and its timing on the primary calendar, is the biggest home-state prize.

Ballots go out to voters Feb. 3, the same day as the Iowa caucuses, meaning that candidates can ill afford to ignore California even as most of them concentrate on trying to get a boost from a strong performance in the Hawkeye State.

While California and Texas results are being tabulated next March 3 — and political insiders expect a war between Harris and former Texas congressman Beto O'Rourke, who has still not announced his candidacy, over Latino voters in those states — it is likely that the outcomes in heavily African-American states further East will already be known.

If Harris can replicate the success Obama and Clinton had in galvanizing black voters in Southern states, she would emerge from those primaries with a huge delegate pad. That remains a big "if" — especially with Booker in the race — but even a strong performance that falls short of total victory would position her well as the national focus turns to Texas and California that night.

For Democrats, delegates are apportioned based in part on the percentage of the vote each candidate gets statewide and in part on the percentage each candidate gets in each of a state' congressional districts — with the proviso that candidates who fail to hit 15 percent get no delegates and have their share of the vote split among those who fared better. In California, there are 53 House districts.

All of that can create a major advantage for a candidate who already has support in every district in the state, or the money to advertise and organize over a long period of time. And history suggests it is hard to catch a candidate who builds a significant delegate lead.

That will be the first of the three big questions facing her campaign to be definitively answered: before results indicate whether she can become the favorite of most African-American voters, before it's evident whether she can execute on her California strategy, comes the challenge of doing well enough early enough to be seen as the top contender as the race heads back to her home state.

In other words, for any demographic advantage or home state edge to come into play, she'll need to make it to Super Tuesday in good shape. If she performed poorly in early states or failed to raise the kind of money she needs to compete effectively through Super Tuesday, the rest could be moot.

Tad Devine, a veteran Democratic strategist who was a top adviser on Bernie Sanders' 2016 campaign, said party voters are most concerned with beating President Donald Trump and will start to make their judgments long before the monthlong voting in California ends.

"If you're going to do well in California, you're going to have to start doing well in Iowa and New Hampshire," he said.

Between the early endorsements from politicians with their own operations in the state and the fact that her campaign management team — Juan Rodriguez, Sean Clegg and Averell "Ace" Smith — has run several of the most effective statewide Democratic campaigns in California in recent years, Harris may have the luxury of standing up an apparatus in the Golden State while she's personally spending time in other states.

"You have to do both," Harris's communications director, Lily Adams, said. "It's important to get to the first few states to introduce herself." But, Adams noted, "you can't start too early" in California.

Of course, the great unknown is whether California Democrats will flock to their home-state senator, favor one of the other choices or splinter enough to prevent any one candidate from turning the state into a treasury of delegates.

Asked Monday whether there was any concern about Harris starting to win commitments in the state, Massachusetts Sen. Elizabeth Warren's communications director, Kristen Orthman, said in an email, "We are in LA today for an organizing event. Did you already know that?"

Los Angeles County Supervisor Hilda Solis, a former U.S. Labor secretary and Democratic congresswoman who has not made an endorsement in the presidential primary, said it was smart of Harris to pick a diverse group of campaign co-chairs who collectively have deep ties to California's various activist communities.

Outsiders will be at a disadvantage if they wait, Solis said.

"You can't just parachute in here," she said.

A big California play makes sense for Harris for another reason: Even if her campaign sputters elsewhere, a win there could give her enough delegates to be influential if there's no clear winner at the end of the Democratic primaries.

Devine, who counted delegates for Jimmy Carter in 1980, said how candidates approach California could be one of the biggest factors on the outcome of the nomination fight.

"That California decision is going to be one of those make-or-break decisions in the campaign," he said.

Harris is counting on it.