The Irish Republican Army dissidents who shocked Northern Ireland this week by killing two British soldiers and a policeman within a 48-hour period have made no secret of their ambition to ignite a new wave of sectarian bloodletting.

But as formerly sworn enemies filed into a provincial church on Friday to mourn as one, the funeral of the slain policeman provided the latest and most powerful demonstration of the ways in which the province’s people and its leaders have united against a return to the violence that racked Northern Ireland for 30 years.

Rallies that drew thousands to silent vigils this week in Belfast and other major towns across the north, and dozens of interviews across the province, suggested that the old antagonists — Roman Catholics and Protestants, nationalists seeking a united Ireland and Unionists committed to keeping Ulster a part of Britain — remain determined to settle their future in peace.

The relative prosperity that peace has brought, the respite from the anguished cycle of killings and revenge, has built a constituency for the power-sharing government in Belfast.

That arrangement, which has worked awkwardly but steadily for 22 months, has given practical form to the reconciliation envisaged in the Good Friday agreement of 1998, which was brokered by the United States.

As much as it was a farewell to the police officer slain on Monday night, Constable Stephen Carroll, the funeral on Friday served, just as much, as a memorial for the two British soldiers killed as they picked up pizzas outside their base in the town of Antrim on Saturday night.

The melancholy of the occasion was captured in the laments played by the lone bagpiper who marched ahead of Mr. Carroll’s black hearse, as it passed through streets lined with thousands of Catholic and Protestant townspeople in the town of Banbridge, 30 miles southwest of Belfast.

But more powerful still was the mood of resolve and defiance evident among the 1,000 mourners in St. Therese Catholic Church.

Some who were there said that never in Ireland’s modern history had there been quite such an improbable gathering of old foes.

Veterans of the Irish Republican Army, spearhead for nearly a century of the drive for the reunification of Ireland, were arrayed in the pews alongside loyalists still pledged to keep Ulster part of Britain.

Politicians and police commanders from both sides of the border sat together, and Anglican and Roman Catholic priests stood beside each other before the altar.

Old adversaries wept together, especially when a choir sang an ethereal version of "Amazing Grace,” a hymn sung often during the funerals of the 3,700 people killed during "the Troubles,” as people in Ireland called the decades of sectarian struggle.

Constable Carroll was in many ways a totem for what has changed.

A 48-year-old Catholic, he spent 23 years in a police force that has historically been Protestant-dominated, but that has changed as radically as anything else in Ulster as the province moves deeper into the peace process.

An avid athlete, he planned to retire in 18 months and become a trainer. He told his wife, Kate, as he left for work on Monday, knowing that dissident republican gunmen still lurked in some of the poorer housing estates of Craigavon, the new town 15 miles from Banbridge where he died, that it would be "ironic” if he should be killed so close to the end of his police service, and when the province was officially at peace.

The Catholic priest who delivered the main eulogy at the funeral, Canon Liam Stevenson, 50, encapsulated the mood with his condemnation of the men from the two dissident I.R.A. groups — the Continuity I.R.A. and the Real I.R.A. — who claimed responsibility for the killings. He said the killers had "abused” the patriotism they proclaimed because "it is robbed of its intrinsic value when it is allied to violence and death.”

Another speaker, Bishop John McAreavey, said that "the people of Ireland have chosen a better way forward, the way of reconciliation and peace, and we are determined not to allow ourselves to be dragged back into the morass of violence.”

But Stevenson’s most striking passage came when he said an attack on the new police force was tantamount to "an attack on the whole population of Northern Ireland.”

Now known as the Police Service of Northern Ireland, it emerged from the Royal Ulster Constabulary, which was widely hated among Catholics for its harsh tactics.

Now, it has been stripped of paramilitary units and has recruited equally among Catholics and Protestants. When he died, Constable Carroll was in an ordinary patrol car, not an armored Land Rover of the kind used by the old police force, part of an effort to show a gentler profile to Catholics.

An equal resolve prevailed among the mourners who streamed throughout the week to lay flowers outside the Massareene army base at Antrim, 15 miles northwest of Belfast.

The bodies of the two soldiers who died there, Sappers Patrick Azimkar and Mark Quinsey, both in their early 20s, were flown back to their families in mainland Britain on Thursday.

Lingered amid the yellow paint markings where the killers left spent shell casings said they wanted nothing to disturb the peace process. Only one man among more than a dozen people interviewed demurred.

Jonathan Johns, a 40-year-old, army-trained medic, who drove 40 miles from his home in Banbridge with his three small children, said he worried about the sincerity of the leaders of Sinn Fein, the political wing of the I.R.A., in the power-sharing government.

"The eyes of the world are on them, so they’re saying the right things,” he said. "But let’s just say I’m skeptical. Who’s to say this wasn’t part of a wider agenda?”

A lunchtime vigil in Belfast on Wednesday drew at least 5,000 people into the plaza before the city hall to listen to a bagpiper playing "Abide With Me,” a mournful Protestant hymn, and to applaud when a rally organizer said the people of the province had shown that "they absolutely and totally reject the murderers.”

"It’s appalling,” Gavin Bell, a 31-year-old civil servant and Catholic, said of the killings. "I’d always thought the dissidents were disorganized and ineffective. Now the worry is whether this is the start of a new campaign.”

One of the week’s most arresting moments came when Martin McGuinness, a former I.R.A. commander who now serves as the province’s deputy first minister, visited Kate Carroll, the policeman’s widow, and called the constable’s killer’s "traitors” who should be turned in to the police, a demand that many in Northern Ireland said no senior member of the republican movement had ever made before.

But Mrs. Carroll’s public remarks may have been the most poignant of all. Before leaving her home for the funeral on Friday, she said that people resorting to violence to settle Ireland’s future should realize that, like her husband, the only "piece of land” they would end up with would be the six feet of a grave plot, and that a broader grasp of that would mean that her husband had not "died for nothing.”

"Why don’t they realize that?” she said.

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