Sanders leads Biden in key Super Tuesday states of California, Texas and North Carolina, polls find

William Cummings | 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.

Former Vice President Joe Biden scored a major victory Saturday in South Carolina's primary, which he says "brought me back" in the race for the Democratic presidential nomination after pulling him within eight delegates of Sen. Bernie Sanders.

But Biden's celebration could prove short-lived, according to polls released Sunday that show Sanders with leads in the delegate-rich states of California, Texas and North Carolina.

Voters in those three states, along with 11 others, will cast their votes on Tuesday, when about a third of all the delegates in the Democratic primary will be up for grabs. The delegates in those Super Tuesday contests are almost 10 times the number available in the first four contests combined.

On Sunday, Biden was already putting a positive spin on what he appears to expect to be a tough day for his campaign.

"Super Tuesday's not the end. It's only the beginning," Biden said Sunday on ABC News' "This Week."

All of the polls were conducted before Biden's decisive win in South Carolina. His campaign will be banking on that win giving him the momentum to gain ground among the voters still weighing their options.

'This campaign has taken off': Biden's blowout win in South Carolina could reshape nomination fight

Here is a look at what the polls found:

California

The Golden State is the mother lode of primary pledged delegates with 415. (Pledged delegates are those won in the primary contests, as opposed to the superdelegates, who would become a factor at the convention if no one has a majority on the first ballot.)

And Sanders appears to be the clear favorite to win the lion's share of those delegates on Tuesday.

"It's going to be very hard to make up the ground in California," Biden admitted on Sunday.

A CBS News poll conducted by YouGov found Sanders as the choice of 31% of likely Democratic voters in California, with Biden in second at 19%. Closely behind the former vice president was Sen. Elizabeth Warren of Massachusetts (18%), followed by billionaire Mike Bloomberg (12%), former South Bend, Indiana Mayor Pete Buttigieg (9%) and Sen. Amy Klobuchar of Minnesota (4%).

Slightly more than half of the respondents said they had definitely decided on their candidate, while 49% left open the possibility that they still might change their mind.

Nineteen percent of the respondents in California said they expected the South Carolina results would be a factor in their decision.

The poll had a margin of error of plus or minus 4 percentage points.

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Texas

Texas has the second-most pledged delegates available with 228.

An NBC News/Marist poll found Sanders leading Biden among likely Democratic voters in the Texas primary 34%-19%. Bloomberg was third at 15%, followed by Warren (10%), Buttigieg (8%) and Klobuchar (3%).

Among those who have already taken advantage of Texas' early voting, the margin was slightly better for Biden. Thirty-three percent of early Texas voters said they cast their ballots for Sanders, 25% said Biden, and 16% Bloomberg.

The poll found Sanders' supporters were the most enthusiastic, with 68% saying they "strongly support" him. For Biden, that number was 52% and for Bloomberg, 51%.

That poll's margin of error among likely Democratic voters was plus or minus 5.3 percentage points.

A CBS News/YouGov poll also found Sanders in the lead among likely voters in the Texas primary at 30%, though by only four percentage points. Trailing Biden (26%) in that poll were Warren (17%) and Bloomberg (13%). Buttigieg and Klobuchar were tied at 6%.

Half of those voters said they were still open to changing their minds, and 21% said the South Carolina vote could affect their final choice.

A third poll, from The Dallas Morning News and the University of Texas at Tyler, also found Sanders in the lead. Among registered Democratic voters and independents who lean Democratic, Sanders was named the top choice by 29%, followed by Bloomberg at 21%, Biden at 19%, Warren at 10%, Buttigieg at 8% and Klobuchar at 4%.

That poll's margin of error was plus or minus 4.05 percentage points.

North Carolina

Sanders also holds a narrow lead in the race for North Carolina's 110 pledged delegates, according to an NBC News/Marist poll with a margin of error of plus or minus 5.1 percentage points.

The poll found 26% of likely voters in the North Carolina primary favor Sanders while 24% said they will vote for Biden. Bloomberg was third at 15%, followed by Warren at 11%, Buttigieg at 7% and Klobuchar at 5%.

Among those who already voted, Sanders led Biden 25%-21%. Another 19% said they had already cast their ballots for Bloomberg, 15% for Buttigieg and 14% for Warren.

Biden and Sanders supporters had about the same level of enthusiasm in North Carolina, with 61% saying they "strongly support" Sanders and 58% saying the same of Biden.

"I think we've got a shot in North Carolina," Sanders said Sunday on CBS News' "Face the Nation."

But Biden predicted he can "win most of the southern states," including North Carolina.

A poll from East Carolina University found Biden with a four-percentage-point lead over Sanders among likely Democratic voters 29%-25%, Bloomberg was third at 14%, followed by Warren (11%), Klobuchar (5%) and Buttigieg (4%).

As in South Carolina, African-Americans make up a large percentage of the Democratic voters in North Carolina. Polling ahead of the South Carolina primary found Biden's support within that voting bloc in the 35%-40% ranger. But he ended up securing 64% of black voters in that contest, according to exit polls.

Similarly, in North Carolina, the NBC News/Marist found Biden as the choice of 36% of black voters and the ECU poll found him at 35%. If black voters break for Biden the way they did in South Carolina, Biden could perform well in the Tarheel State.