Intransigence seemed to be winning out over idealism once again in Northern Ireland early today, as political leaders failed to resolve a dispute over disarmament of rival militia groups -- an issue that has stalled implementation of last year's Good Friday peace agreement.

The deadline for striking a deal -- midnight Wednesday -- came and went, but Gerry Adams, leader of the Irish nationalist party Sinn Fein, and his chief adversary, David Trimble, had only angry words for each other after three days of talks centering on when the various paramilitary organizations in this battle-scarred British province will give up their guns.

There was no word from British Prime Minister Tony Blair, who set the midnight deadline, on what steps he might take if the parties fail to agree. As the critical hour passed on a blustery Belfast night, there was no deal, and at 3:30 a.m., he told the exhausted negotiators to go home, get some sleep and report back about midday for further talks.

With Blair and Irish Prime Minister Bertie Ahern present to pressure local political leaders, the scene here was a familiar one to the 1.6 million residents of Northern Ireland who have seen their hopes for peace soar -- with the historic agreement signed on Easter weekend 1998 -- and then stumble as politicians embarked on a year of arguments over the terms of the deal they had signed.

President Clinton, who has played a steady role in the Northern Ireland peace talks, spoke with Blair by phone Wednesday night and offered to intercede with participants in the talks if that would help. Blair asked the president to stand by, but the disagreements were evidently too great for a transatlantic call to make a difference.

Deadlines tend to be flexible in Northern Ireland, and there was still some hope that some kind of settlement could be reached. Overall, though, the pessimists seemed to be in the majority.

The Good Friday agreement recognizes that Northern Ireland will remain part of Britain as long as a majority of voters here choose to make it so. That was a difficult pill to swallow for Sinn Fein, the political arm of the paramilitary Irish Republican Army, and others in the predominantly Catholic nationalist camp who want to break with Britain and unite with the Republic of Ireland.

The nationalists accepted that principle largely because they were given a chance to take part in a new local government created under the Good Friday plan. In an election last year, Sinn Fein won enough votes to earn two seats in the 10-member cabinet that will oversee the local government.

But Trimble, leader of the largely Protestant majority that wants continued union with Britain, was elected first minister, or governor, of the province, and he refuses to institute the new cabinet until militia groups that have fought each other for decades begin "decommissioning," or giving up their weapons. The agreement does not require decommissioning until May 2000, but Trimble says the spirit of the compact demands a rule that he describes as "No guns, no government."

Trimble's insistence is aimed primarily at the Irish Republican Army, which has refused to disarm before the new government is fully in place. For months, Sinn Fein has said it does not have the power to make the IRA disarm and that, in any case, there is no requirement for it to do so until next May.

Sinn Fein took a small step toward compromise Wednesday, agreeing to declare that it expects the IRA to surrender its weapons by next May. But Trimble dismissed this, saying that a declaration of an expectation is too vague to bridge the gap in negotiations.