Superdelegates are back in the news - with Bernie Sanders and his campaign believing that they're a path to winning the Democratic nomination, and with Hillary Clinton's campaign seeing them as their true firewall in this contest.
Who are these superdelegates? What role do they play? Can they switch sides? How many have done so in the past? How did the 2008 Obama-vs.-Clinton superdelegate fight play out? And do they actually have super powers? (Fortunately or unfortunately, the answer to that last question is no.)
Below are the answers to everything you wanted to know about superdelegates:
What is a superdelegate? And who are they?
Superdelegates are unpledged delegates to the Democratic convention, meaning that they aren't beholden to the results from primaries and the caucuses (the way pledged delegates are). They are, for the most part, current and former Democratic politicians. Former President Bill Clinton is a superdelegate; so is current Sen. Bernie Sanders.
They make up 15 percent of all delegates (714 out of 4,765) - down from 20 percent in 2008. And they are free to support the presidential candidate of their choice at the convention. According to NBC News' latest count, Clinton leads Sanders in superdelegates, 460-38. One catch: Superdelegates have to be present at the convention for their vote to count.
Among pledged delegates, Clinton leads 1,288 to 1,042.
Can superdelegates switch sides?
Yes. And this is one of the arguments that Sanders' campaign has made - that the superdelegates who are supporting Clinton now might back Sanders later. "We think some of these superdelegates who have now supported Hillary Clinton can come over to us," Sanders told MSNBC's Rachel Maddow last month. But some caution here: In the 2008 race, no more than about 30 superdelegates switched from Clinton to Barack Obama before Clinton dropped out of the race in early June 2008, according to former Obama campaign officials. And that is after Obama took the lead in pledged delegates.
Do they reflect the will of how their states voted?
No. Superdelegates can support whomever they want, despite how their state voted. Sanders and his campaign have argued that superdelegates should be mindful of these voters' preferences. "In … states where we've won by 25 or even 30 points, I think it is not unreasonable for the people of those states to say to their super delegates, 'Hey, how about representing the people of our state and the outcome of the caucus or the primary?'" Sanders also told Maddow. Yet even under such a system - where superdelegate support goes to the candidate who won the state or territory - Clinton would still top Sanders in superdelegate pledges, 260 to 138.
Have they ever contradicted the pledged delegate total?
No. Since they were established beginning in the 1984 presidential cycle as a way to give party leaders more say in the process, superdelegates have never changed the outcome of the primary season. "The superdelgates are politicians, and politicians generally try to agree with voters and follow the will of the voters," said Elaine Kamarck of the Brookings Institution, who was on the 1980s commission creating the superdelegates. But Kamarck - who happens to be a superdelegate supporting Clinton - says they view that voter will with more of a national than state-by-state focus.
When do they count?
The Sanders campaign argues that superdelegates don't officially count until they vote at the convention, though the same is true of the pledged delegates. Yet news organizations, such as NBC News, include both pledged delegates and superdelegates in their delegate-tracking counts - the same way they kept track of the 2008 Clinton-vs.-Obama race.
How did the 2008 superdelegate battle play out?
On the Super Tuesday of the 2008 Democratic race, Clinton enjoyed a lead of about 100 superdelegates over Obama, according to NBC's count back then. But that superdelegate advantage began to shrink after Obama held a sustained advantage in pledged delegates. And Obama overtook her in superdelegates at the end of the primary season. By contrast in this cycle, Clinton is the candidate with the pledged-delegate lead (1,288 to 1,042), and her superdelegate edge has widened as the contest has gone on.