CHICAGO — As the Democratic National Committee huddled ahead of a major vote to reform the presidential nominating process, members quarreled over whether the party should pass the rule change as some party leaders sought to hold onto their special delegate status.

The debate over what to do about unpledged delegates — members of Congress, governors, DNC members, and other party officials known as “superdelegates” — dominated the three-day gathering at the Hyatt Regency in Chicago, notably located across the street from a towering Trump hotel.