The Irish Republican Army's decision to renounce violence teaches an important lesson: Terrorism can be beaten.

The period known in Ireland as "the Troubles" lasted a quarter-century, from about 1970 to the mid-1990s, when the IRA declared a ceasefire. During that time, the IRA murdered about 1,800 people -- politicians, police officers, soldiers and ordinary citizens. When the campaign of violence was at its height, it sometimes seemed it might never end. The "hard men" of the IRA were ruthless, dedicated, well-armed and well-funded. No compromise seemed possible between their goal of a united Ireland and the determination of Northern Ireland's Protestant majority to remain British.

Yet at some point along the way, theIRA was forced to a sobering conclusion. Though armed struggle had gained the organization enormous international publicity, it was not advancing its cause. Far from driving the British from Ireland,violence had made them dig in their heels. Meanwhile, in Ireland -- north and south, Protestant and Catholic -- people grew more and more sick of the mayhem and bloodshed. Terrorism works, it is often said, which is why so many politicalmovements have embraced it. But if confronted with intelligence and resolve, it can be overcome. In Northern Ireland, terrorism was failing. In yesterday's statement, the IRA finally acknowledged that fact.

Skeptics were quick to point out what the IRA did not say in its communiqué. It did not say it was disbanding. It did not say it was ending its campaign to unite Ireland and force Britain out of the north. It did not express any regret for its reign of terror; on the contrary, it insisted that "the armed struggle was entirely legitimate." It did not accept the role of Northern Ireland's police force or say explicitly that it was giving up its sideline of robbery, extortion and other crimes, though it did order its militants to stick to peaceful work and not to engage "in any other activities whatsoever."

Even so, it was by far the strongest and clearest signal yet that the IRA is indeed turning away from violence. The fact that the organization has ordered its militants to "dump arms" is significant, as is the commitment to continue an independently supervised disarmament process, even if doubt remains about when and how decommissioning will actually take place. Most significant, the IRA has pledged to "assist the development of purely political and democratic programs through exclusively peaceful means [italics added]."

The British government deserves a large part of the credit for the IRA's turnabout. Prime Minister Tony Blair's slogan about law and order (tough on crime, tough on the causes of crime) could just as easily describe the government's approach to IRA violence. It was certainly resolute when the IRA attacked, keeping troopson the streets of Northern Ireland when necessary, bringing in controversial emergency measures to help it combat the threat, and even sending the elite Special Air Service to track down militants. Atthe same time, though, the government conducted several rounds of secret talks with the IRA, trying to bring it to thetable.

All the while it worked on improving the conditions of Catholics in Northern Ireland, hoping to pull up the roots of violence by improving schooling and job opportunities. Finally, after it became clear that the IRA was backing away from violence, it set up an (admittedly off-and-on) Catholic-Protestant power-sharing arrangement in the north, opened investigations into alleged abuses by the police and security services, and reformed the much-disliked Royal Ulster Constabulary, the local police force.

But if the subtlety and resolve of the British government was critical, the IRA's own behaviour was key, too. Atrocities such as pub bombings helped turn people against the organization and destroy its self-made image as a disciplined group of noble nationalists. Over time, it became clear that many IRA men were simple thugs. That was brought home after some of them knifed to death a young Belfast Catholic, Robert McCartney, outside a bar earlier this year. A big IRA bank robbery brought the criminality of the IRA under even more scrutiny.

To a large degree, the IRA defeated itself. So, over time, will other terrorist groups,if democratic countries can only stand firm.