More than seven years have passed since the Good Friday Agreement was reached. Almost four years have elapsed since the first IRA act of decommissioning in October 2001. Two major attempts to secure what would have been a Good Friday Agreement II were launched in the past two years, but they ended in recrimination. This conflict followed decades, indeed centuries, of disputed history, and so it is natural that the IRA statement yesterday has not been received with universal rejoicing. It will take months, possibly longer, before it becomes clear whether this is really an historic breakthrough. Understandable scepticism should not, however, mean that the IRA’s words are not taken seriously.

This statement is different in character from the dozens of pronouncements issued previously. The words used yesterday, at the urging of Tony Blair and Bertie Ahern, leave little room for multiple interpretation. An “armed campaign”, which has theoretically been in a state of “ceasefire” since 1997, is officially declared to have ended. A machinery for decommissioning involving General John de Chastelain and his team, and representatives of the Roman Catholic and Protestant Churches, has been described. The instruction that “volunteers must not engage in any other activities whatsoever” is as close as the IRA leadership could come to prohibiting what it regards as “fundraising” and “policing”, but which almost everyone else views as organised crime and “punishment beatings”.

There is, furthermore, a logic in both the content and the timing of this statement. The prospect of a “return to war” disappeared altogether after the atrocities of September 11, 2001. The recent bombings in London have only reinforced the reality that “political terrorism” of the sort witnessed in several western European countries, but most prominently Ulster, during the 1970s must end. There is no turning back.

The IRA would doubtless have preferred to make this move only after the negotiations involving Sinn Fein and not in advance of a full and final settlement. The combined impact of their past prevarication, the marginalisation of the Ulster Unionist Party by the Rev Ian Paisley’s Democratic Unionist Party and the outrage sparked by the murder of Robert McCartney have, at last, forced the IRA’s hand.

A further element to this equation should be recognised. The American dimension has been critical to the peace process and to Sinn Fein, in particular. Under Bill Clinton, on this and other issues, the US Administration certainly “talked the talk” but failed to “walk the walk” with sufficient clarity and consistency. Mr Clinton was too willing to take the personal pledges of the Sinn Fein high command at face value (and to claim the credit for them) and did not demand that those promises were fulfilled. The peace process could not, for all the President’s charm, work as a private club. There were also members of his staff who saw the IRA as a romantic organisation. Unionists, correctly, did not see Washington as an honest broker.

There has been no such ethical uncertainty from the Bush White House. The President has made it plain that terror is terror and that Sinn Fein would receive no red carpet from him while the IRA equivocated over the armed struggle.

There will, quite properly, be much talk about how to ensure adequate verification. On the matter of arms, there is an Alice in Wonderland aspect to this discussion. As no one knows with absolute precision what stockpiles IRA members collectively hold, there is no means of ensuring that all have been disposed of, whether the dumping of weapons is merely witnessed, photographed or broadcast on live television. The republican movement remains flush with funds, so even if every bullet and bomb were decommissioned today, the ammunition could be replaced tomorrow. These are inevitably imperfect circumstances. There is no practical alternative for the people of Ulster, Unionist or nationalist, but to trust the International Commission on Decommissioning.

On the broader theme of criminal behaviour, though, it is possible to be more specific. The International Monitoring Commission (IMC), which was denounced by Gerry Adams and Martin McGuinness when it was established, can now, paradoxically, provide proof of IRA intentions. The IMC has published a series of reports, which have exposed the extent to which individuals and units linked to the IRA have engaged in smuggling and other forms of robbery. They also show how far the IRA regards itself as having the right to impose its warped notion of justice on nationalist communities.

The IMC should be asked to accelerate its activities. Reports should be produced every three months or so and not twice a year as at present. If two successive documents suggest that the IRA has indeed desisted from criminality, the conditions will exist for the two Governments to ask all parties to reconsider the political package that fell apart last December. If a further IMC inspection indicates that the IRA has continued to stick to its word, it should be possible to move towards fresh elections for the Northern Ireland Assembly and the restoration of devolution. Any accord will be fragile, and additional detailed investigations by the IMC would be required.

There is plenty of room left for disappointment. The IRA may be unwilling or even perhaps incapable of delivering what it outlined yesterday. There may be senior Unionist politicians, handcuffed to their own past rhetoric, who are unable to take “yes” for an answer even if that is palpably what is being presented to them. There is, nonetheless, more cause for hope that at any moment since the Good Friday Agreement. For Ulster itself, the rest of the United Kingdom and Ireland, it could be the beginning of the end.