Actually, the DNC has a contractual and fiduciary responsibility to stay neutral in a primary, because they sign contracts to that affect.
Section 4 of the Democratic Party charter reads this way:
"In the conduct and management of the affairs and procedures of the Democratic National Committee, particularly as they apply to the preparation and conduct of the Presidential nomination process, the Chairperson shall exercise impartiality and evenhandedness as between the Presidential candidates and campaigns. The Chairperson shall be responsible for ensuring that the national officers and staff of the Democratic National Committee maintain impartiality and evenhandedness during the Democratic Party Presidential nominating process."
The chairperson was Debbie Wasserman Schultz, who resigned / was fired earlier today. The CEO of the DNC is Amy Dacey. But look at their emails and tell me if that lives up the charter.
Some of us are suing.