Story highlights Superdelegates are party officials who are intended to help play an oversized role in the nominating process

Hillary Clinton campaign chairman John Podesta is scheduled to speak to top donors on a conference call

(CNN) Hillary Clinton has at least one thing to be thankful for: Superdelegates.

"That is her only true firewall," an adviser glumly said Wednesday in the wake of a humbling New Hampshire defeat that has shaken the confidence of the candidate and the campaign.

For Clinton, who remained out of public view Wednesday, it's a day of assessing strategy, reassuring donors and planning for how to confront Bernie Sanders at their debate on Thursday in Milwaukee.

Campaign chairman John Podesta is scheduled to speak to top donors on a late-afternoon conference call about the state of the campaign, two people familiar with the call said, describing it as an opportunity to put supporters at ease and urge them to work harder in hopes of competing with Sanders' fundraising juggernaut.

Superdelegates are party officials who are intended to help play an oversized role in the nominating process -- to protect the party. That's what is at play here. Of course, we all remember how dozens of Superdelegates jumped ship in 2008 and went running toward Obama after he won their districts. (Paging John Lewis!)

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