The announcement by the IRA yesterday that it had ended its “armed campaign” against Britain and that its members had been ordered to engage in exclusively political and democratic methods from now on is, on the face of it, a historic development and has been welcomed as such by the White House and the British and Irish governments.

The IRA’s 30-year campaign of violence to force Britain’s withdrawal from Northern Ireland was one of the longest lasting and most destructive in modern European history, resulting in the deaths of more than 1,800 people and bombing campaigns that several times devastated the commercial heart of London and other English cities.

At a time when London is once again a terrorist target, this time at the hands of Islamic extremists, the ending of the IRA’s campaign is particularly good news for Prime Minister Blair. But it will be greeted elsewhere in the world, not least in Washington, as welcome evidence that it is possible to bring terrorism to an end.

That said, there are dangers that the significance of the IRA move may be overstated. Mr. Blair called it “a step of unparalleled magnitude,” which it may well be. But he called another, earlier move by the IRA – to decommission its weapons – “a seismic shift” and that turned out to be a deep disappointment when the IRA refused to disclose any details of its disarmament to the public.

In one sense, the IRA statement is meaningless. Ordering an end to its campaign against Britain can be seen as merely formalizing the reality of the last eight years or so, which is that the IRA cannot return to violence.

The cease-fire that it called in 1997 was enormously popular in Ireland and resulted in considerable electoral success for the IRA’s political wing, Sinn Fein, which now holds seats in the London, Dublin, Belfast, and European parliaments. Returning to war would imperil those political gains, while resuming terrorist violence in a post-September 11, 2001, world would undoubtedly lead to the isolation and shunning of leaders such as Gerry Adams, who these days likes to don the mantle of an international statesman. With renewed violence an unrealistic option, yesterday’s statement was cost-free for the IRA.

What many people looked for in yesterday’s statement was an indication that the IRA would begin the process of going out of business and start disbanding itself. Nowhere in the statement was there a sign that this had become possible.

IRA disbandment became an issue because of two extraordinary events at the turn of the year that pitched the Irish peace process into crisis and forced yesterday’s statement. The first was the audacious robbery of a bank in Belfast that netted the IRA more than $50 million. The other was the vicious stabbing to death of a young Belfast Catholic man, Robert McCartney, by an IRA gang – followed by an attempt to cover up IRA and Sinn Fein complicity.

Those events demonstrated two things. One was the IRA’s drift into criminality from political violence. Aside from robbing banks, the IRA now runs a multimillion-dollar business smuggling fuel, counterfeiting DVD’s and CD’s, selling stolen cigarettes, and running extortion rackets. It invests the proceeds in legitimate businesses, the profits of which either go back into the group or into the pockets of leaders. No one who has studied the IRA believes for a moment that these activities will stop because of yesterday’s statement.

The other lesson was that the hitherto accepted test of the IRA’s peaceful bona fides – decommissioning its weapons in a transparent fashion – had been made largely irrelevant. The problem highlighted by the two incidents was not that the IRA had weapons but that it existed at all. The IRA did not require crates of AK-47 rifles nor tons of explosives to destabilize the peace process; all it needed to rob the Belfast bank and stab to death was a sufficient number of motivated members.

Those lessons were most certainly digested in America where a range of politicians including Senators Kennedy, Clinton, and McCain called for the IRA to disband. While neither Mr. Blair nor his Irish counterpart, Prime Minister Ahern went so far, they made it clear that they wanted evidence the IRA was prepared to start withering away or to morph into an Irish version of VFW.

They got neither in yesterday’s statement. Not only that, but the statement was noticeable for the absence of any commitment to cease recruiting new members. Thus it is possible not only that the IRA will survive, but that it could grow.

The importance of all this is not that it means the IRA could go back to bombing and shooting people, but that it will retain enough in terms of potential and actual illegal activity to keep the pot boiling and to prevent the Irish peace process coming to a successful and final conclusion.

The “Good Friday” deal of 1998 – in which Unionist parties, which favor retaining Northern Ireland’s British links, agreed to share power with Sinn Fein – has been suspended because of the collapse of trust in the IRA. The fate of one Unionist leader, David Trimble, who was toppled when the IRA failed to deliver on its promises, has convinced many that the IRA’s real objective is not to achieve peace but permanent instability.

For that reason, many will treat yesterday’s IRA’s statement with caution. The IRA’s words were fine, but there have been fine words before followed only by disappointment. This time round, few will disagree that the prudent course will be to wait a considerable time to see whether the IRA’s rhetoric is matched by actions, or rather the lack of them.

Mr. Moloney is author of “A Secret History of the IRA.”