California, here they come: Sanders dominates new USA TODAY/Suffolk poll of Super Tuesday's prize

Susan Page | USA TODAY

Show Caption Hide Caption What is Super Tuesday and why is it important? A previous version of this video displayed an incorrect date in a graphic. It was 1988 when 14 Southern and border states held their primaries.

Bernie Sanders holds a commanding double-digit lead on the cusp of California's Democratic primary, a new Suffolk University/USA TODAY statewide poll finds, giving the Vermont senator the prospect of capturing the lion's share of the largest trove of convention delegations in the country on Super Tuesday.

Sanders was at 35% among likely Democratic primary voters, well ahead of former New York mayor Mike Bloomberg at 16%, former vice president Joe Biden at 14% and Massachusetts Sen. Elizabeth Warren at 12%.

The survey, taken Wednesday through Saturday by landline and cellphone, doesn't reflect whatever bounce Biden may get from his solid victory in the South Carolina primary Saturday night.

Even so, the poll showed the depth of Sanders' standing in the state. "Sanders will win California because he is winning 45% of Hispanic voters and 59% of young voters," said David Paleologos, director of Suffolk's Political Research Center. "No Democratic opponent can offset both of these statistical advantages to close his advantage."

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The poll of 500 likely Democratic primary voters has a margin of error of plus or minus 4.4 percentage points.

On Sunday, Biden argued that his strong showing had made him the clear moderate alternative to Sanders, portraying it as effectively a two-person race.

But Biden's hopes for a comeback face a double challenge in California: finishing ahead of Bloomberg, who also portrays himself as the strongest moderate contender, and reaching the 15% threshold needed to claim a share of convention delegates allocated by the results statewide and in its 53 congressional districts.

California has 415 pledged delegates, 271 of them allocated by district and another 144 awarded statewide. The state's delegation comprises more than one-fifth of the 1,991 votes needed to claim the presidential nomination at the Democratic National Convention in Milwaukee in July.

If his rivals fail to reach the 15% threshold statewide and in some congressional districts, Sanders' sweep would make it much more difficult for other candidates to catch up in the rest of the primaries.

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But the California survey also shows what could happen if voters consolidated behind a single moderate alternative to Sanders, who describes himself as a Democratic socialist. For instance, the combined support of Bloomberg, Biden, Pete Buttigieg and Amy Klobuchar would total 42%, seven points higher than Sanders' current standing.

Among the lower-ranking candidates, Buttigieg, the former mayor of South Bend, Indiana, was at 7%; Minnesota Sen. Klobuchar at 5%; and liberal activist Tom Steyer and Hawaii Rep. Tulsi Gabbard at 3% each. Steyer dropped out of the Democratic contest Saturday after a disappointing finish in South Carolina.

California looms a test as well for Bloomberg, who will be on the ballot for the first time Tuesday. The billionaire has spent an unprecedented amount of his own fortune on TV ads nationwide, including more than $63 million in California alone, according to Advertising Analytics, which tracks candidate spending.

In the Suffolk/USA TODAY poll, one in four likely Democratic primary voters reported that they had already cast their ballots, which means their vote can't be affected by Biden's bounce or Bloomberg's final TV ad push. Thirteen percent in that group voted for Biden, well behind Sanders (27%), Warren (22%) and Bloomberg (17%).

That said, fewer California voters have returned their early ballots than at this point in previous contests, according to an analysis by Political Data Inc., reported by Politico. That could reflect a desire by some to see how the race was sorting out before deciding.

California traditionally has held its primary in June, often after the presidential nomination was settled. This year, the nation's most populous state moved up to Super Tuesday on March 3, when a total of 14 states and a territory will vote. The number of delegates at stake swamps those allocated by the first four contests, in Iowa, New Hampshire, Nevada and South Carolina.

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In the California poll, Sanders' support was disproportionately young, male and liberal. A 51% majority of liberals backed the Vermont senator, compared with 17% of moderates and 12% of conservatives. Biden did best among moderates, Bloomberg among conservatives. Sanders was supported by a stunning 59% of those 35 and younger – no other candidate broke into double digits – and by 45% of Hispanics.

Sanders' recent comments praising the Castro regime in Cuba for its literacy and health programs carried some cost to him: 25% said they made them less likely to support him; 8% said they made them more likely to support him. There was a generational divide on Sanders' remarks: Among those 56 to 65 years old, 36% said the comments made them less likely to support Sanders. Among those 35 and younger, less than half that number, 17%, felt that way.

Attitudes also were divided on whether the Democratic candidate who arrives at the convention with the support of the most delegates should be nominated, even if he or she hasn't reached a majority. Under party rules, if no candidate wins the nomination on the first ballot, unpledged "superdelegates" would be able to vote on the second ballot. Many of those party regulars are considered more likely to back Biden than Sanders.

An overwhelming 79% of Sanders' supporters said the candidate with the most delegates should be nominated, even if he and or she hasn't reached the majority. Just 44% of Biden backers agreed.

Suffolk University and USA TODAY took a separate survey of 300 likely Democratic primary voters in Contra Costa County, a bellwether county in California that since 2004 has recorded voting returns that closely track the statewide results.

In Contra Costa, Sanders was at 34%, Bloomberg at 18%, and Biden and Warren at 11%. The poll, taken by landline and cellphone Wednesday through Saturday, has a margin of error of plus or minus 5.7 points.