The death toll was the highest since the Troubles began three decades ago. Condemnation of the bombers rolled in swiftly from around the world. “This is an appalling act of savagery and evil,” said British Prime Minister Tony Blair. Queen Elizabeth offered her “heartfelt sympathy.” The White House said the violence would not derail President Clinton’s planned visit to Northern Ireland, scheduled to begin on Sept. 3.

The question now: will the bombing derail the tenuous peace agreement negotiated last spring? That deal, the Good Friday Agreement, was a historic act of accommodation by unionists and republicans and was supported overwhelmingly by voters. Terrorists on both sides of the Protestant-Catholic divide have tried to kill the agreement with the occasional bombing or shooting. But the peace process–spurred on by unrelenting pressure from London, Washington and Dublin–has trundled on nonetheless.

Blair vowed not to let the Omagh massacre “wreck the prospects for peace.” Of the people behind the blast, he said: “We will pursue them to the utmost in order to bring them to justice for this terrible deed. These people will never be allowed to win.”

Just who “these people” are was not clear in the immediate aftermath of the Omagh bombing. But security sources north and south of the border were leaning toward pinning the blame on a small group that calls itself the Real IRA. Just last week–and prior to the Omagh bombing–Patrick Byrne, commissioner of the Garda, the national police force of the Republic of Ireland, warned that the Real IRA posed a serious threat to the peace process. He issued his warning after a bomb–perhaps one as large as 1,000 pounds–was detonated along the border. It appeared to be a test explosion carried out on a vacant piece of land. According to Garda security sources, the Real IRA consists of breakaway IRA paramilitaries and is not under IRA control. Some unionists, especially hard-liners, are skeptical. The Rev. Ian Paisley, an outspoken leader of Ulster’s Democratic Unionist Party, said there is no such thing as a republican bombing free of IRA fingerprints. “We have had far too much double talk,” he said. “No one can do a bombing anywhere in Northern Ireland without the knowledge of the IRA and without their collusion in it.”

Violence stuns but never comes as a complete surprise in a place as volatile as Northern Ireland, where more than 3,000 people have been killed in sectarian violence since 1969. As Ireland mourns its dead, the challenge for its people is difficult: to ensure that in the end, peace prevails, not terrorism.