PHILADELPHIA — Liberal groups demanding an end to the Democratic Party's superdelegates system handed over a half-million signatures to members of the convention rules committee Saturday ahead of a critical meeting.

"We have 53 committee members signed on as co-sponsors," said Aaron Regunberg, of Rhode Island, who is a member of the DNC rules committee, at a press conference at the convention center. "That's well beyond the threshold for a minority report to bring this to the floor. We are excited to have this debate and we're excited to push forward. We are not going to be satisfied until we are going to be able to bring this to an actual vote, which is what this party needs."

The DNC rules committee meets Saturday afternoon to discuss amendments to the Democratic Party charter, where liberals will make their case to ditch superdelegates.

The issue has caused a divide among Democrats. The liberal wing of the party has for months been pushing to eliminate superdelegates, who are generally establishment Democrats. They play a critical role in deciding who will get the nomination, and party leaders say they keep grassroots candidates from gaining traction.

While Hillary Clinton beat Bernie Sanders decisively in the Democratic primary, her dominance of the superdelegates made a Sanders victory virtually impossible.

"We are going to be making this case as vociferously as possible," said Regunberg, the sponsor of the amendment. "We think there will be a lot of support on the floor, when we bring it to the floor."

The move to alter the superdelegate system has some high-level support.

House Minority Leader Nancy Pelosi, D-Calif., said in May she wants the party to reduce the role of superdelegates in the nominating process.

"I think it just makes people think, 'Well, wait a minute. We're going through an electoral process, and then you're telling there are 500 people in Washington, D.C., who are going to weigh at the end?'" Pelosi said.