In the minds of many Sanders supporters, superdelegates are proof of a rigged system. In reality, concern that Democratic elites will run away with the presidential nomination is very likely overblown. Superdelegates aren’t bound by the popular vote, but they tend to line up behind whoever amasses the most pledged delegates, party representatives who back candidates based on the results of a primary or caucus. If the race is extremely close, however, superdelegates could effectively act as a tie-breaker. And if voters believe that the party has sabotaged their favorite candidate, they could be angry enough to sit out the general election, whether or not the perception has much basis in reality. That could hurt the party’s odds of winning the White House in 2016 and deepen the rift on display in the midst of an increasingly contentious primary fight.

Sanders faces a steep uphill primary battle, but if he were able to alter the trajectory of the race, superdelegates could defect to his campaign. Superdelegates can still switch their allegiances, and Democratic Representative Raul Grijalva of Arizona, a superdelegate who has endorsed Sanders, says that at least some superdelegates in Congress have already expressed regret at making up their minds so early on. “It’s now a competitive race with an opportunity to win,” Grijalva says. “Nobody factored that in, [and they] locked themselves into a commitment that they’re having a very difficult time getting out of. He added: “The people in the party that read tea leaves have done a poor job in this election of reading the tea leaves. I think it was presumed that this would be an anointment process that we were going to go through and it would be over. Now that it’s not, people that I think would have been more thorough in looking at everything are wishing they had that chance again.”

For now, nothing is set in stone. The 2008 primary election demonstrated how superdelegates can and do gravitate toward whichever candidate appears to have a popular mandate. Clinton initially held a strong superdelegate lead over Barack Obama. But as Obama’s candidacy gained momentum, superdelegates opted to back his candidacy in increasingly larger numbers. “By definition, we’re talking about political professionals. They would go against the will of the voters at their own peril,” says Elaine Kamarck, a superdelegate supporting Clinton and the author of Primary Politics: Everything You Need to Know About How America Nominates Its Presidential Candidates.

Still, it won’t be easy for Sanders to sway superdelegates. The Clinton campaign has focused on amassing a pledged-delegate lead, a strategy that has so far proved extremely successful. At this point in the race, Clinton holds a commanding lead in both pledged and superdelegates. “While we’re proud of the support for Hillary Clinton from Democratic governors, senators, and other leaders who have been working for our party,” Jesse Ferguson, a spokesman for the campaign says, “our strategy continues to be maintaining our strong lead with pledged delegates.” Earlier this month, Clinton campaign manager Robby Mook emphasized that the campaign plans to build on that pledged-delegate “lead even further making it increasingly difficult and eventually mathematically impossible for Sen. Sanders to catch up.” As long as it holds, superdelegates are virtually certain to stand by the Clinton campaign.