AUSTIN - What wins presidential elections: star power or aggressive voter outreach?

It is a question that has been raised repeatedly in connection to the 2016 Republican primary, but it is now being tested on the Democratic side in Texas, where former U.S. Secretary of State Hillary Clinton is counting on endorsements and an army of high-profile surrogates to lock down a long-expected victory despite months of intense organizing by the campaign of U.S. Sen. Bernie Sanders.

Actor Ted Danson, figure skater Michelle Kwan, television personality Star Jones and another former secretary of state, Madeleine Albright, have all come to the state to campaign for Clinton in recent days, in addition to the candidate and her husband, former President Bill Clinton. She also is endorsed by all of Texas' major newspapers, the state Senate Democratic caucus and almost all of the Democratic members of Congress from the state.

Sanders' most prominent Texas endorsement has come from former agriculture commissioner Jim Hightower, who last held office in 1991. Sanders campaigned Saturday in the capital and near Dallas, but before that, his organization had not held any public events in Texas in more than seven months.

Quietly, however, the Sanders campaign has built a robust outreach program led by more than half-a-dozen paid staffers who have been on the job since early November. Clinton hired her first paid staff in Texas late last month.

A Sanders campaign official told the Houston Chronicle it had made about 3 million phone calls to Texas voters. The Clinton campaign declined to provide a number, but two sources familiar with the operation said it probably had made "way fewer" than 1 million.

Nervous Clinton supporters

The differing strategies will come to a head Tuesday, when Texas holds it primary on one of the most important days of the presidential election. A dozen states vote on so-called Super Tuesday, and none are nearly as big as the Lone Star State, where 251 delegates are at stake - more than have been awarded in all of the previous contests combined.

Clinton, who has long-standing ties to the state, is expected to win easily. But Sanders has steadily closed the gap as his campaign has gained momentum nationally and his staffers here have reached out to voters.

Seven public opinion polls conducted in the past two weeks have shown Clinton with an average lead of 59 percent to 33 percent, a dominant edge but a far cry from a year ago, when Clinton led Sanders 62 percent to 5 percent.

The narrowing in the polls has helped force Clinton to air at least five television and radio ads in the state, and it has made some longtime supporters a little nervous.

"She's going to do really well in Texas, and it's going to send a message to the rest of the country," said Vickie Vogel, 69, a retired lawyer and party official from La Grange, between phone calls after a speech by Albright last Thursday morning at Clinton's Austin headquarters. "I think. I mean, I hope."

The stakes are enormous: The delegates are important, but potentially more crucial is the message. Clinton's victory Saturday in South Carolina put pressure on Sanders to prove his viability with a strong performance Tuesday, especially among African Americans and Hispanics voters in the South, where his message has not resonated as well. Clinton, on the other hand, has been favored here by so much for so long that anything less than a landslide would project weakness nationwide.

"Texas is one of the biggest, most powerful states in the union. Winning it is a key to any primary. Period," said Hector Nieto, a former state party official who served as President Barack Obama's Texas director in 2012.

Nieto, who has not endorsed either candidate, said Sanders must come close in Texas to remain competitive nationally while Clinton must win or her campaign will suffer a "very big body blow."

Focus on Latinos

Aware of the stakes, the Clinton campaign starkly ramped up its efforts in the past week, particularly through ads and surrogate visits. Bill Clinton is scheduled to return Monday for three events, including one at 8 a.m. at the Buffalo Soldiers National Museum in Houston.

Carlos Sanchez, a spokesman for Clinton's Texas campaign, disagreed with the idea that she has not been fighting for Texas or that the campaign has relied on celebrities.

"We are working hard to deliver a strong result in Texas come Tuesday," Sanchez said in a statement, arguing that, "for 40 years, she has had a special relationship with Texas, going back to her time registering Latinos to vote in 1972, and that's why she enjoys such enthusiastic support here."

Latinos have been a major focus of Clinton's efforts here. The ads that the campaign unveiled last week included a Spanish-language radio message and a TV spot that showed the candidate talking with a 10-year-old girl concerned about her parents being deported. Clinton's camp feels it has an opening on those issues because Sanders voted against an immigration reform bill in 2007.

"That's not sitting well with a lot of us, particularly those of us who know Hillary's role in working for farmworkers and coining the phrase, 'Si, se puede' (Yes, we can)," said state Sen. Sylvia Garcia, D-Houston, at a Latinos for Clinton event last Monday in Austin.

Sanders has defended himself by saying he voted against the bill because of a provision that would have allowed for the mistreatment of guest workers.

Garcia added Sanders would be hurt by a video that emerged that showed his supporters in Nevada shouting "English only" at Latina activist Dolores Huerta during a speech at the Nevada caucuses.

Clinton supporters said the campaign's strategy for winning over Texas Democrats also focuses on the frustrations felt by women in an anti-abortion state and the pragmatic tendencies that come from being a political minority.

"It is incredibly important to have leaders who know, like Hillary knows, to not throw the baby out with the bathwater – to know how to work across the aisle," said actress American Ferrera in a subtle dig at Sanders during an event at an Austin bar Friday.

Trust in Sanders

Sanders supporters, on the other hand, said the senator's unique appeal to Texas is rooted in the fact that he is a straight shooter with a populist message.

"Texas voters appreciate honesty and consistency," said Rania Batrice, a campaign spokeswoman, adding that, "America's No. 1 populist, Jim Hightower, is from here in Texas, and he has endorsed Bernie Sanders."

One attendee at the Sanders rally Saturday pointed to another reason: Texans have trusted Clinton before, and she has let them down, he said.

"I voted for Clinton in the 2008 primary," said Jeremy Holmsley, 29-year-old Austin delivery truck driver. "But all of these things coming out - the emails, and the Wall Street speech transcripts - it's kind of suspicious."

Sanders has repeatedly demanded Clinton release the transcripts of her speech to Wall Street firms and he did so again at the rally, which his campaign said drew 10,000 people to the Circuit of the Americas racing track in Austin.

Despite the public polls, the Sanders camp has expressed hope for a Texas victory or at least a strong showing.

"Even coming close is a victory for Bernie Sanders in the state of Texas, given where he started," said former state Sen. Hector Uribe, D-Brownsville, who helped introduce Sanders at the rally. "Just finishing with some good numbers is I think going to resonate with people in the states that vote afterward."

Hybrid delegate system

How the votes are spread will also matter, as the Texas Democratic primary awards delegates through a hybrid system that is mostly based on totals in specific areas but also includes a chunk to be split up proportionally according to the statewide vote.

Experts said there are several things they will be watching, including vote totals among Latinos.

Victoria DeFrancesco Soto, a political scientist at the University of Texas, said Clinton is likely to win that key voting bloc, but probably not by as much as expected because of the inroads made by the Sanders campaign.

Name advantage

Harold Cook, a former executive director of the Texas Democratic Party, said he will be watching to see which of the two distinct campaign strategies will pay off.

Cook said he thought the Sanders voter outreach would help him, but not by enough to come close because of Clinton's name recognition and longtime support.

"It is kind of a luxury to be able to waltz into the state at the last minute and hold a few rallies and you're gonna win," Cook said. "That's the luxury of being Hillary Clinton, for better or for worse. She does minimal effort, and she's gonna win."