The leader of Northern Ireland's biggest political party outmaneuvered rebels within his own ranks Saturday, winning support for the peace accord that hard-liners are trying to destroy.

The executive committee of the Ulster Unionist Party - which represents half of Northern Ireland's pro-British Protestant majority - voted 55-23 to support the historic agreement and their leader, David Trimble.But outside Ulster Unionist headquarters, police held back Protestant hard-liners shouting "Traitor!" at the departing Trimble, who faces a less certain battle to win Protestant hearts and minds.

The agreement to end 30 years of violence was struck Friday among eight parties - including Trimble's bitter enemy, the IRA-allied Sinn Fein party. It would create a new local government for Northern Ireland but require its members to cooperate with the predominantly Catholic rest of Ireland.

Sinn Fein leader Gerry Adams faces many of the same difficulties as Trimble in trying to sell unpalatable compromises to militant grass roots.

In his first test of public opinion Sunday, Adams will address one of scores of demonstrations by IRA supporters in both parts of Ireland to commemorate the rebel Easter Rising of 1916 - a traditional rallying point for anti-British warmongers.

"Both David Trimble and, I suspect, Gerry Adams will have difficulty in persuading their natural constituencies that this is the best deal," former British Prime Minister John Major told the BBC.

Other aspects of the agreement, such as a promise to parole several hundred Irish Republican Army prisoners within two years, have angered many Protestants.

Trimble acknowledged the vote fell short of a clear-cut endorsement but cleared the way for a more difficult vote next Saturday involving more than 700 members of the party's governing Ulster Unionist Council. He suggested the dissent was a healthy sign of democracy.

"We are not some Stalinist party," he said. "We allow people to express their views freely."

During the acrimonious five-hour meeting, Trimble took the audience through the 67-page agreement paragraph by paragraph, noting points that favored their shared aim of defending Northern Ireland's union with Britain.

Trimble said he won the vote in part because of his argument that "to be effective as a party, we must remain united."

Afterward, half of the party's 10 members in the British Parliament said they remained critical of the accord, which must be passed by a referendum in Northern Ireland on May 22.

Ian Paisley, leader of the Democratic Unionists, said he was "looking forward to giving Mr. Trimble a bloody nose on May the 22nd."