It looked frighteningly like the bad-old days: Gunmen, claiming to be members of a splinter group of the Irish Republican Army, attacked a group of British soldiers on Saturday outside of Belfast, killing two and seriously wounding two others and two civilians.

It was the first deadly assault on the British military in Northern Ireland since the 1998 Good Friday peace agreement laid a path for ending 30 years of sectarian violence. Less than 48 hours later, a police officer was also killed. This is a crucial test for the province’s political leaders — Catholic and Protestant — and the power-sharing accord that has become a model for societies looking to end religious and ethnic conflict.

We are encouraged that all sides immediately condemned the Saturday attack.

Peter Robinson, the province’s first minister and leader of the mainly Protestant Democratic Unionist Party, called it “a futile act by those who command no public support and have no prospect of success.” Martin McGuinness, the former I.R.A. commander who is deputy first minister, said the dissidents want to restart a war and he would “deny their right to do that.”

Although their power-sharing government is still fragile, we hope the two leaders are as committed as they seem to making it work. That must include every effort to arrest the gunmen and shut down the dissident group, which calls itself the Real I.R.A. And it must include repeated firm warnings to their respective constituencies of how much everyone will lose if there is a resurgence of bloodshed.

The British prime minister, Gordon Brown, traveled to Northern Ireland on Monday, which was a welcome sign of solidarity and reassurance. Mr. Brown should resist any calls to put British troops back on the streets in Northern Ireland. The police — with a carefully created sectarian balance that now includes about 25 percent Catholics — took control of security in 2007. This is an important symbol of political reconciliation. Mr. McGuinness, however, may want to rethink his opposition to the police chief’s decision, after Saturday’s attack, to deploy a limited number of British Army specialists to help with surveillance in Northern Ireland.

The Real I.R.A. claims to be the true voice of Northern Ireland. It is up to the province’s leaders and Britain, with strong backing from Washington, to prove them wrong and show them that a handful of thugs will not be allowed to deny Northern Ireland its hard won peace.

http://www.nytimes.com/2009/03/10/opinion/10tue2.html?pagewanted=print

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