The DNC is the non-profit organization that controls fundraising, ballot access, and ultimately defines what "the democrats" are. If you are elected into office as a "democrat" you have sworn fealty to unelected organizations known as the DNC, or the DCAA and a few others. Make no mistake. The reason Hillary was the presumptive nominee is because she had paid those orgs and so do all the other "who's who" of the democratic party. For all intents and purposes, if you are a "democrat" you are there because the various unelected powers have allowed you to be.