While I love this attack on the DNC, I am at a loss to figure out just what legal theory would support a non-member of a political party suing the party. Sanders is not a Democrat but an Independent. Can someone explain this coherently.
The suit that is still in court is a class action suit brought by voters, in the U.S. District Court for the Southern District of Florida.
Bernie Sanders supporters are suing the DNC: Here's what you need to know
That article includes a link to the complaint, and the complaint lists the claimed grounds for relief, starting on page 27 of the complaint.
The claimed legal theories for money damages are: Fraud, Negligent Misrepresentation, Violation of 28-3904 of the D.C. Code (Defendants misrepresented as to material facts that had a tendency to mislead), Unjust Enrichment, Breach of Fiduciary Duty, and Negligence.