LOS ANGELES — Ever since President Trump’s election, California has fashioned itself as a kind of center of the resistance to his administration. With Democrats overwhelmingly controlling both houses of the State Legislature, lawmakers here have looked for every opportunity to counter the White House. But California is also home to a reliable bastion of centrist voters, particularly in Orange County and the Central Valley.
Ahead of Super Tuesday, polls suggest that Senator Bernie Sanders of Vermont is leading with a comfortable margin here, but many voters have indicated that they were waiting for results in early states before casting their ballot. So despite the state’s liberal reputation, it is not a given that voters will overwhelmingly back Mr. Sanders. Among the other candidates, former Vice President Joseph R. Biden Jr. has received some of the most high-profile endorsements in the state and Michael R. Bloomberg has poured hundreds of millions of dollars into advertising and hiring staff in California.
In 2016, California was something of a firewall for Hillary Clinton, who beat Mr. Sanders with 53 percent of the vote to his 46 percent. Democrats in California voted for Ms. Clinton in 2008, too, with 51.5 percent choosing her over Barack Obama. California is many things, but predictable is not one of them.
Here’s everything you need to know ahead of Super Tuesday in the Golden State:
How much does California matter?
A lot. Some 415 pledged delegates will be rewarded based on the results in California — the biggest haul of any state in the country and more than all four early states combined. With so much still unclear in the race, what happens in the country’s most populous — and arguably most liberal — state will play a key role in who becomes the nominee and ultimately shape the fate of the Democratic Party.
What kind of turnout should we expect?
As of Sunday, roughly 3.2 million ballots had been mailed in, suggesting a high turnout, but more than 16 million ballots had been mailed out, suggesting that many more people will send in ballots and show up at the polling places at the last minute. Pollsters in the state expect high levels of turnout, but have been cautious about predicting record-breaking numbers.
What do the polls suggest?
Several polls in recent days show Mr. Sanders with a comfortable lead. The most recent poll, released Friday by The Los Angeles Times and the University of California Berkeley Institute of Governmental Studies shows Mr. Sanders leading all of his rivals by a 2 to 1 margin. In that poll, Senator Elizabeth Warren of Massachusetts came in a distant second, with 17 percent, a significant fall after leading in the state months ago.
A Public Policy Institute of California poll found Mr. Biden trailing in second, with several other candidates bunched around him, including Ms. Warren and Mr. Bloomberg.
Before the Nevada and South Carolina contests, Monmouth University released a poll showing Mr. Biden in second and found that just under half of voters were open to changing their minds.
All of the polls suggest that it is possible only two or three candidates could reach the 15 percent viability needed in any individual congressional district to earn delegates. That would make it possible for Mr. Sanders to win half the delegates in the state even if he wins only one-quarter of the total vote. And all of the polls suggest one group is helping Mr. Sanders’s numbers: Latinos, particularly young Latinos, whom the campaign has aggressively courted.
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What do the demographics of expected voters tell us?
There are more than 6 million no-party-preference voters in the state, a figure that skews younger, suggesting that many California voters don’t align with either party. Roughly 53 percent of the expected 14.5 million voters will be white voters, compared with about 26 percent Latino, 15 percent Asian-American and 6.5 percent black voters, according to a forecast by the Latino Policy and Politics Initiative at the University of California, Los Angeles.
How has the state’s shift to an earlier primary affected the race?
California has long been a political A.T.M. for both parties. But this year’s Democratic primary has made it so that candidates are focusing in on areas that have long been ignored — including the Inland Empire and the Central Valley. The primary is not a winner-take-all contest: Delegates are awarded based on how candidates do in each of the congressional districts. So, for example, Mr. Bloomberg has focused much of his investment on Orange County, where Democrats flipped several congressional seats in 2018.
Who has spent the most money and time in the state?
Mr. Sanders has held several high-profile rallies in the state over the last several months, including recently in Santa Ana, and a pair in San Jose and Los Angeles on Sunday. Mr. Biden, by comparison, has kept a relatively low profile in the state, and has not invested much time or energy in field operations in the state either.
Nobody has put more money into the primary than Mr. Bloomberg, who has also spent lavishly in the state, sending millions of campaign mailers to voters daily for more than a week. Mr. Bloomberg has spent more than $66 million on television so far, according to Advertising Analytics, an amount that drastically dwarfs all other candidates. Tom Steyer, who dropped out of the race after the South Carolina primary on Saturday, spent $32 million on television, compared with Mr. Sanders’s nearly $7 million. While Ms. Warren did not spend her own campaign money, a super PAC supporting her spent roughly $3.6 million.
Who has received important endorsements?
Many of the state’s most high-profile politicians, including Gov. Gavin Newsom, have stayed neutral since Senator Kamala Harris dropped out of the race late last year. (Though his wife, Jennifer Siebel Newsom, backed Ms. Warren on Friday.) Ms. Harris herself has not made any public comments about the remaining candidates, and neither has Jerry Brown, the popular former governor and former presidential candidate.
While Mr. Sanders leads in popular support in the polls, he has received few endorsements from elected officials in the state. Several initial backers of Mr. Biden have switched their allegiance to Mr. Bloomberg, who also has the support of several African-American mayors in the state, including London Breed of San Francisco. But Mr. Biden did receive the endorsement of Mayor Eric Garcetti of Los Angeles, and on Sunday, former Senator Barbara Boxer threw her weight behind Mr. Biden as well.
Who can vote in the California primary?
In short, any citizen and California resident. If you’re a registered Democrat, simply show up to your local polling place or one of the many voting centers. What if you’re registered no party preference or not even registered here at all? Same thing — the California Legislature approved same-day voter registration, allowing anyone to cast their ballot on the same day they sign up, which can be done at any polling place in the state. Did you get a ballot mailed to you at home that you’ve let languish on your kitchen counter for weeks? Simply put it in the mail (no stamp necessary) or get it to the most convenient polling site.
When will we know who won?
That’s hard to say. Exit polling will undoubtedly give us some idea, but because of all the laws that are designed to make it easier to vote, it is virtually impossible that all the ballots will be counted by Tuesday night. As California officials are fond of saying, that is a feature, not a flaw, of the system.
Have you seen or experienced any problems voting using the new machines? We want to know at CAtoday@nytimes.com.