Bernie Sanders has the advantage on Super Tuesday as rivals jockey to hold down his delegate count

What has been a state-by-state battle over the past month will suddenly explode into a nationalized contest on Tuesday, with establishment Democrats worried about the strength of Sen. Bernie Sanders, I-Vt., but not settled on the strongest alternative.

Former vice president Joe Biden, with his blowout victory Saturday in South Carolina, made a strong case that he should be that person, but Super Tuesday voters will barely have time to digest those results before they, and the candidates, are plunged into the biggest and most important day of the Democratic nominating campaign.

By the time the votes from Tuesday's contests are counted, and all the delegates allocated, at least two things should become clearer. One is whether Sanders has emerged with an insurmountable lead in the delegate race. The other, if Sanders' delegate lead is not so big, is whether Biden or someone else might be positioned to overtake him. 

Sanders heads toward Super Tuesday's contests in an enviable position. But given growing resistance to his candidacy among establishment Democrats, he needs a strong performance Tuesday to put a lock on becoming the delegate leader heading to the national convention in Milwaukee in July. 

"Bernie is the clear front-runner, but he's got to get a lead, and a substantial lead, to consolidate his position," said Tad Devine, who worked for Sanders's campaign in 2016 and who advised Andrew Yang this year. 

No day on this year's primary-caucus calendar sets up any better for Sanders than this year's Super Tuesday. One reason is his perceived strength in California, where 415 delegates will be distributed. Other factors include the higher percentage of Latino voters in some of the Super Tuesday states, particularly Texas with its 228 delegates. Beyond that, primaries in the future are mostly closed, denying Sanders the votes of independents, one of his best constituencies.

Campaign strategists can't say just how well Sanders will be positioned after Super Tuesday. There are simply too many variables - too many candidates, too much fluidity and too many combinations about possible outcomes. Campaigns have been modeling the states and constantly tweaking internal projections. As one strategist put it: "It's an insane Rubik's cube." 

Campaign advisers to both Biden and former New York mayor Mike Bloomberg say they will be best positioned to become the principal alternative to Sanders after Super Tuesday. But the campaign of former South Bend, Indiana, mayor Pete Buttigieg believes he could be competitive and has been strategic about where he has put resources.

Sens. Amy Klobuchar, D-Minn., and Elizabeth Warren, D-Mass., appear to have even higher hurdles than the others to score well Tuesday. Warren has turned to a super PAC for advertising help after decrying the use of such groups throughout her campaign. Warren's super PAC spending, roughly $15 million, is of concern to the Sanders campaign because of her potential to attract voters who otherwise might support him.

Bloomberg is counting on the massive amount of advertising he has done to help boost his chances. According to Advertising Analytics, as of the beginning of last week, he had spent about $160 million on television ads in the Super Tuesday states and was at that point scheduled to spend about $35 million more in the final week. But he has been slowed by a poor debate performance in Nevada and attacks on his record since then.

Contrast that with Biden, who at the beginning of last week had spent nothing on television ads in the Super Tuesday states and, according to his campaign, will invest about $2 million in radio and TV ahead of Tuesday's voting. Instead, Biden is counting heavily on a boost from South Carolina and support from African American votes there and elsewhere.

Sanders, according to the Advertising Analytics figures, will come in around $14 million to $15 million in TV, and his campaign has targeted the money to have the maximum impact on competitive districts. But he has organizations that appear to eclipse those of any of the other candidates, and his team has sought to use rallies in states with early voting to encourage supporters to go directly to the polls to bank votes ahead of Tuesday.

Super Tuesday has been a fixture of Democratic nominating contests since 1988, the brainchild of Southern Democrats seeking greater influence with the hope that it would boost moderate candidates. That didn't work out as they had hoped, but the concept of a big day of primaries in early March stuck. 

In 2008, Super Tuesday had grown to more than 20 states, including California, Illinois, New York and New Jersey. It became known as "Super Duper Tuesday" or "Tsunami Tuesday." That year saw Barack Obama and Hillary Clinton battle for an advantage, and one victory of the Obama campaign was to shift the media's focus from who was winning big states to the trench warfare of delegate accumulation.

This year, almost the entire focus of Super Tuesday will be on delegates. The landscape this year is smaller than in 2008, but still sprawls across 14 states with votes also in American Samoa and among Democrats abroad. The 14 states include 164 congressional or state Senate districts that will award the majority of delegates. In all, 1,357 pledged delegates - 34 percent of the total for the year - will be awarded.

Two factors make this year's event different from those in the past. One is that Super Tuesday falls just three days after the South Carolina primary, rather than 10 days as it was in 2008. That gives candidates little time for serious campaigning in most of the states and raises the question of how much impact Biden's victory in South Carolina will have on voters elsewhere. The other difference is that the field of candidates competing Tuesday is larger than on previous Super Tuesdays.

Estimates of delegate totals and of Sanders' possible margins vary significantly. At the high end, say strategists inside the campaigns as well as outside analysts, Sanders could emerge from Tuesday's contests leading his closest competitor by 300 to as high as 400 delegates. That would put him firmly in command of the race though still might leave him short of a majority going into the convention. 

At the lower end of estimates, the consensus is that Sanders's delegate margin could be in the range of 200 or 250. That would still give Sanders the advantage but could be a more manageable margin to overcome for one of the other candidates, but only if the field quickly shrinks after Tuesday.

One non-campaign analysis calculates that Sanders could win between 600 and 700 delegates on Tuesday with the next-highest candidate in the range of 300 to 500. Sanders could emerge with a 2-to-1 lead over his closest challenger, but still well below 50 percent overall. But these are merely possible scenarios, not predictions, and were all based on information before South Carolina voted.

Faiz Shakir, Sanders's campaign manager, sought to play down suggestions that Sanders will come out of Super Tuesday with a lead of more than 300, saying of the lower-end projections: "If you gave it to me, I'd take it." He said Super Tuesday could provide additional momentum that would put Sanders in a stronger position for contests later in March and in April.

Sanders has long criticized the Democratic National Committee for what he saw as the establishment helping Clinton and hindering him in the 2016 campaign. Today, ironically, he stands to benefit, potentially significantly, from the rules that determine the distribution of delegates.

Nevada's Feb. 22 caucuses offer an example of how Sanders is benefiting. Sanders got about one-third of the raw vote in Nevada. After realignment, the process by which people whose candidate has not hit the 15 percent threshold move to support another candidate, his county convention delegate number hit about 47 percent. Ultimately, he was awarded 24 of the 36 delegates to the national convention, which means from one-third of the initial raw vote, he was able to pick up two-thirds of the national convention delegates.

The caucuses provide an extreme case of this kind of allocation, but the overall rules could work similarly in Sanders's favor by giving him a share of the delegates disproportionate to his raw vote percentages. So far, the highest percentage of the vote he has received in any contest was in Nevada. In Iowa and New Hampshire, he got about a quarter of the popular vote. But he is benefiting from the fact that no other candidate has consistently broken through the 15 percent threshold statewide and in congressional districts.

"There is a lot of difference between 34 percent of the delegates versus 47 percent of the delegates," said Daron Shaw, a professor of government at the University of Texas at Austin. "If he's in the low 30s, I think it's a different story."

Heading into Tuesday, the fractured opposition gives Sanders a potentially significant advantage. The senator from Vermont is the only candidate who is broadly viable across all the states and districts, meaning he is likely to break the threshold in almost every congressional or state Senate district. 

The other candidates are in a more tenuous position, hovering in polls somewhere just below or just above the 15 percent threshold that determines viability for delegates. No one can predict with any certainty how any of the others will do in the district-by-district competition, but their individual and collective results will shape both their and Sanders's delegate hauls.

The rules stipulate that any candidate who gets 15 percent or more in a district, or statewide, receives a delegate. If Sanders and only one other candidate hit 15 percent or more and the others fall below that, they would split the delegates, although not necessarily evenly. But if four candidates hit the threshold in a district with four delegates, everyone gets one delegate, meaning even if Sanders is the leader, his total would be held down.

"If Bernie ends up in a situation where he can run up a large enough margin where there is only one other candidate hitting that threshold, that's a big victory for him," said Ace Smith, a California-based strategist who was a senior adviser in the presidential campaign of Sen. Kamala Harris, D-Calif. "If he has two or three people, that's not so good because it will profoundly affect the delegates."

At this point, campaigns are focused on districts more than states, hoping to maximize their delegate counts by putting higher priority on districts whose demographics appear more favorable - for Biden, that means districts with higher concentrations of African Americans - or that have substantially more delegates to award than average. All the campaigns are focused as well on districts with an odd rather than even number of delegates to award.

One big advantage for Sanders is the role California will play on Tuesday. He lost the state to Clinton in 2016, but he currently is the leader in the polls there and, according to Democrats not associated with campaigns, has a deeper organization than any other candidate. 

California offers early voting and vote-by-mail to everyone and, as of Thursday, nearly 3 million people had returned their ballots. More early ballots are being returned, according to Paul Mitchell, a California strategist who tracks the numbers. But percentages tell the other part of the story, which is that Republicans are returning their ballots more rapidly than are Democrats. 

Two Democrats said that on the basis of their analysis and reporting, more people than ever are waiting possibly until Election Day to return those ballots and hoping they have a better sense of the shape of the race by then. 

Republicans are behaving as they have in past elections, turning in ballots at the same rate, but Democrats are lagging. "Anybody who's waiting is not for Bernie Sanders, and they're trying desperately to make their vote count," said Gale Kaufman, a Sacramento-based strategist.

The other reality about Super Tuesday is that the results will not be known immediately. Counting in California will continue into the following week, and with so many candidates on the edge of viability, the final numbers could look different than they appear on the day after voting.