A bitter dispute over Democratic Party rules that critics say enhance the power of insiders over rank-and-file voters came to a head Saturday when a key party committee defeated a proposal to end the role of so-called superdelegates.

But proponents of the reform measure said they are undeterred, and promised a floor fight at the party's national convention later this week.

"I think this was a missed opportunity," said state Rep. Diane Russell of Maine, who promised that backers of the measure would take the proposal to the full convention, which starts Monday at the Wells Fargo Center. "We may not win, but we are going to fight."

Throughout the primary season, supporters of candidate Bernie Sanders complained bitterly that the superdelegate system tilted the odds in favor of presumptive nominee Hillary Clinton.

Under current rules, some 15 percent, or 712, of the party's delegates in the presidential nominating process are officially uncommitted and can vote for the candidate of their choice, regardless of the popular vote result. Critics of the system charge that the superdelegates - members of Congress, local elected officials, and other party leaders - generally tend to favor entrenched interests and, in this election, shifted the balance of power to Clinton.

The proposal offered Saturday before the Democratic Rules Committee would end the role of superdelegates so that all Democratic presidential delegates would be allocated according to the vote totals of each candidate.

The complaint that the current system is unfair gathered force Thursday with the release by WikiLeaks of 20,000 emails sent among Democratic Party officials, some suggesting that party leaders, who are supposed to be neutral, favored Clinton.

"It is a core belief that our process should reflect our core values," said Rhode Island Rep. Aaron Regunburg, who offered the amendment to end the use of superdelegates Saturday at the party rules committee hearing, held at the Convention Center. "Our superdelegate system is self-evidently not reflective of those principles. If we want to bring our party together to fight the hate-filled campaign of Donald Trump, then I can think of no better way to do it."

Shortly before the vote, Texas Rep. Sheila Jackson Lee spoke out against the proposal, arguing that the superdelegate system broadened the participation of minorities in the presidential nominating process.

"There are elected officials all over this country who have become superdelegates," she said. "This is an opportunity to participate." Sanders supporters held a news conference before the vote, vowing to fight for the superdelegate-rules changes. During the packed hearing, those who did not make it inside the room could be heard chanting: "No superdelegates. No superdelegates."

The amendment was defeated by a vote of 108 to 58. But, because more than 25 percent of the delegates voted in favor of the proposal, it will be included in a minority report to the full convention, creating the opportunity for a floor debate.

During the campaign, Clinton accumulated more than enough delegates, including superdelegates, to win the nomination - 2,807, well above the threshold of 2,472. Of that number, Clinton will receive 602 superdelegate votes; Sanders, 48. A small number of delegates remain uncommitted.

Quite apart from the issue of superdelegates, Clinton's supporters contend that she won the nomination fair and square, because she prevailed in the popular vote over Sanders, a firebrand socialist who argued throughout the campaign that Clinton was the candidate of entrenched special interests.

But Russell, the Maine representative, argued Saturday that the popular vote totals miss the point. The perception early on that the party establishment was putting its collective finger on the scales for Clinton and that the overwhelming majority of superdelegates were backing her created an uphill fight for Sanders, who had trouble shaking the perception - at least in the initial phase of the campaign - that a Clinton win was inevitable.

"It is a fundamentally elitist argument to say that there are folks at the top who know better than anyone else," Regunburg said.