PITTSBURGH — Hillary Rodham Clinton loyalists tried yesterday to kill off the caucus system that proved so damaging to her presidential bid, but were beaten back by a Democratic Party leadership firmly under the command of Barack Obama.

Democrats who supported Clinton's candidacy pushed to amend the new party platform so that caucuses would be banned in future presidential nominating contests.

But the party's platform committee refused to allow the amendment to come up for a vote or even a discussion. Co-chair Patricia Madrid, a former New Mexico attorney general, said the matter would instead be taken up at later date by the party's Rules Committee.

That left Clinton supporters disappointed. They contend that if the party were serious about enfranchising more voters, it would take a clear position against a caucus system that discourages participation by shift workers, the disabled and overseas members of the military. In traditional primaries, people have all day to vote. But a caucus might last just a few hours.

During the Democratic race, Obama outmaneuvered Clinton in Iowa and many other states that held caucuses, turning out far more supporters and racking up enough delegates to give him an insurmountable lead.

"My feeling is the issue should have been aired and people should have had the opportunity to speak and vote it up or down," Bob Remer, a delegate for Clinton from Chicago and a member of the platform committee, said yesterday. Remer had put forward the amendment that was shelved. "The caucus system is the exact opposite of everything I've been fighting for in terms of maximizing democratic input."