If there is one belief that unites Sen. Bernie Sanders’ supporters, it is that the Democratic Party establishment and the corporate-run media will use any means possible to prevent his nomination. As evidence, they point out that Sanders fought Clinton to virtual tie in Iowa, soundly thrashed her in New Hampshire with a larger-than-expected victory and this past weekend came in a very close second in Nevada. In the all-important race for delegates, Clinton and Bernie are tied with 51 pledged delegates each as they head to South Carolina.

And yet, according to the AP delegate counter, Clinton holds a whopping 502 to 70 lead over Sanders in total delegates earned so far, putting her one-quarter of the way to the 2,383 needed to win the Democratic nomination. How can this be, they ask?

The answer, of course, is that Clinton has racked up a substantial lead among so-called “superdelegates” — leading party members include senators, representative, governors and other party officials who under Democratic Party nomination rules are formally free to back any candidate they choose, no matter the results of specific nominating contests. And that lead is likely to only increase after voting in South Carolina, the next contest in the Democratic nomination race, where media reports indicate half of South Carolina’s six superdelegates back Clinton, while the remaining three, so far, remain neutral.

[SEE:Editorial Cartoons on the 2016 Presidential Elections]

If current trends hold, Clinton’s substantial lead among superdelegates will make it very difficult for Sanders to secure the party’s nomination. That’s because the 712 superdelegates, who have an automatic berth in the nominating convention, constitute about 15 percent of the 4,746 total delegates up for grabs during the nominating process. At this point, media reports indicate Clinton has secured the backing of 451 of those superdelegates, compared to only 19 who have publicly committed to Sanders.

Not surprisingly, Sanders’ backers argue that the role of superdelegates is completely undemocratic, and can only serve to thwart the party will as expressed through actual voting in primaries and caucuses. Already, a group of Sanders supporters has started a petition, which currently has attracted almost 190,000 signatures, pressuring superdelegates to align themselves with “regular voters” when casting their nomination votes. Meanwhile, the progressive organization MoveOn, which is backing Sanders, has vowed to track commitments from superdelegates and to target those individuals who have not pledged to support the will of the voters.

In theory, the “Feel the Bern” crowd has a point: the role of superdelegates is undemocratic, and by design. Democrats first established superdelegates in 1984. The goal was to provide a means for party leaders to prevent the more ideologically extreme members of the party from nominating a candidate who could not win in the general election, as happened with George McGovern in 1972. Even Jimmy Carter, who surprised party regulars by securing the nomination in 1976, was not viewed as the strongest party candidate by many party leaders. It is worth noting, however, that in 1984 most superdelegates backed Walter Mondale over Gary Hart, only to see Mondale get crushed by President Ronald Reagan in the general election.

These experiences raise a crucial question: How do superdelegates decide which candidate to back? Fortunately, we have some evidence based on a study of the 2008 Democratic presidential nominating contest, in which the balance of superdelegates backed then Sen. Barack Obama, helping him clinch the nomination. Political scientists who looked at this race found that superdelegates had to juggle often competing considerations.

[SEE: Editorial Cartoons on Hillary Clinton]

As illustrated by Moveon and the Feel the Bern crowd today, they frequently faced intense pressure from well-defined and often ideologically extreme groups. But they also understood that who the presidential nominee was could affect their own electoral chances in November, depending on who local voters supported. Moreover, they needed to be cognizant of the consequences of backing the wrong candidate for their future power prospects, and for the chances of getting their policy preferences enacted.

The choice regarding who to back, then, was not simple and it pointed in different directions for superdelegates depending on their particular political context. Moreover, that context changed through the course of the nominating contest, which further complicated their choices.

Nonetheless, the authors do discern some patterns guiding superdelegates’ choices in 2008. Not surprising, given what we know about elected representatives’ focus on re-election, personal electoral considerations loomed large. Those superdelegates who endorsed Clinton usually did so because of strong constituency support for her in their home districts. They could justify their decision by pointing to the wishes of local voters. However, as perceptions of Obama’s electoral prospects grew more positive nationally during the nominating process, it allowed many superdelegates, particularly those less cross-pressured by local factions, to back him by arguing that he would be more likely to unify the party come November. In short, the Clinton and Obama superdelegates used slightly different calculations in deciding which candidate to support.

What does this suggest for how the Democratic superdelegates will break in this nominating process? For those representing very liberal districts, or who have a strong progressive policy agenda, it may make sense to back Sanders. But to the degree that Clinton is perceived to be closer to the median Democratic voter in most districts, the electoral considerations influencing elected superdelegates will favor her.

The lesson of 2008 for Sanders, then, is that to break the local ties that bind superdelegates to Clinton, he is going to have to begin winning races, and by decisive margins, to demonstrate that he is electorally viable come November, much as Obama’s surprisingly large victory in the 2008 North Carolina primary prompted a flurry of superdelegates to announce for him. In this regard, the March 1 Super Tuesday contests, in which Democrats choose more than 1,000 delegates in 12 contests, loom especially large.

[SEE: Democrat Cartoons]

If Clinton runs the table, with Sanders only winning his home state of Vermont, it will signal to the superdelegates that he’s not likely to be competitive come November, and it may trigger a flurry of additional endorsements for her in an effort to unify the party behind her candidacy and end Sanders’ bid. On the other hand, if he can carry a handful of states, including Colorado, Massachusetts, Minnesota and Oklahoma, as well as Vermont, and runs competitively in other contests, many superdelegates may be reluctant to endorse quite yet.

In the ideal world for Sanders supporters, of course, if he can stay competitive past Super Tuesday and remain close in the pledged delegates count, followed by significant victories in large states like California, Pennsylvania and New Jersey down the road, he may get some superdelegates who have endorsed Clinton to reconsider their initial choice. Remember, because delegates are apportioned proportionally in most early contests, Sanders doesn’t have to win every contest on Tuesday to remain competitive in the delegate contest.

But at some point, if Clinton is to feel the Bern, he has to win larger states and by decisive margins. At this point, that’s a long-shot proposition . It remains to be seen whether SuperTuesday will change those dynamics.

More from U.S. News

Editorial Cartoons on the 2016 Presidential Elections

Editorial Cartoons on Hillary Clinton

Political Cartoons on the Democratic Party

Super Tuesday Is Key for Bernie Sanders Winning Over Superdelegates originally appeared on usnews.com