As the Democratic presidential primary heads to high-stakes contests in New York and Pennsylvania, Sen. Bernie Sanders' campaign says it's confident that he'll secure the nomination if he wins the most "pledged" delegates to the national convention.
These are the delegates chosen in primaries and caucuses.
What really annoys the Sanders campaign team is when political observers automatically include so-called "superdelegates" in their count of what's needed to win the Democratic Presidential nomination.
Jeff Weaver, Sanders' campaign manager, told CNN that it's important to remember that these superdelegates can always change their mind before the national convention.
“They don't count until they vote, and they don't vote until we get to the convention,” Weaver said.
Weaver thinks if Sanders can win a plurality of the elected "pledged" delegates, then many superdelegates will swing Sanders’ way.
“What this campaign is looking for, and what the senator is looking for, is going into the convention and coming out with the nomination,” Weaver says.
There are just over 700 superdelegates who are not selected in the primary process. About a third of them are elected Democratic officials, including members of the U.S. Senate, the U.S. House and state governors.
The second group, which makes up about two-thirds of the total, are state party officials.
Currently, roughly 500 superdelegates have made a commitment in this race, and the vast majority support Clinton.
Retired Middlebury College political science professor Eric Davis thinks Weaver has a legitimate argument with the "unelected" party officials.
“The question that can be asked about those people is, 'Who elected them? To whom are they accountable?’ And I think it would be very difficult for officials who are not themselves elected to go against the will of the voters as expressed in primaries and caucuses,” Davis says.
But University of Vermont political science professor Garrison Nelson thinks Sanders will have a hard time winning these party officials over because he hasn't run as a Democrat for most of his political career.
“Bernie's first 10 elections were run against Democrats, and Democrats remember that,” Nelson says. “Democrats remember that."
Sen. Patrick Leahy is a superdelegate who is supporting Hillary Clinton.
Leahy now says he'll support Sanders if Sanders ends up with the most "pledged" delegates, according to Caroline Dwyer, Leahy's 2016 campaign manager.
Professor Davis says it won't be easy for Sanders to win a plurality of pledged delegates. Davis says Sanders will have to win upcoming primaries in New York, Pennsylvania and California with between 55 and 60 percent of the vote to achieve this goal.