Sanders supporters and grassroots activists delivered a petition with 600,000 signatures demanding the Democratic Party end the use of unelected officials to help determine presidential nominees.

The supporters protested outside the DNC Rules Committee by banging on the doors and chanting “let us in!” but were kept out by security.

They are protesting to eliminate superdelegates in future elections, saying that it holds too much power in the nominating process. They believe that Sanders’ campaign was hurt by Hillary Clinton’s overwhelming support from superdelegates.

The amendment was defeated. However, it gained enough support to force a floor vote at the upcoming convention.