None of this means that Mr Major was wrong to seize the opportunity for peace in Ireland. The alternatives were few. Attempts to crush the IRA ruthlessly, without much regard to the consequences for civil liberties, failed in the 1970s. Complete British withdrawal from Northern Ireland has commanded much public support but very little among politicians. The pre-ceasefire policy - a low-level state of war in which the authorities attempted to keep casualties to an acceptable level - was leading nowhere. Its prospects might have been better if the British had tried more imaginative forms of government in Ulster, such as establishing vigorous, independent local councils, instead of treating it as though it were an unruly colony. The pre-ceasefire policy ("we shall never talk to terrorists") was, indeed, the principled way to proceed, even if it brought no immediate prospect of an end to violence. But modern Western societies value human lives - and freedom from fear and inconvenience - more highly than they value principle, and it is hard to argue that they are wrong.
In that sense, the ceasefire is a success even if the peace process is not. It has saved perhaps 100 lives, and a thousand limbs. It has brought a new freedom and vigour, and a precious sense of normality, to Ulster's cities. Every month that passed, Mr Major calculated, made it harder for the paramilitaries to go back to violence. The Prime Minister's strategy was to spin it out, to lean first this way and then that way, to keep everybody talking and hoping - a little flexibility on decommissioning for the nationalists, a proposal for an elected assembly for the Unionists. This is the art of parliamentary politics and Mr Major is a master of it. The trouble is that the IRA despises the parliamentary way. What works for the jobbing politicians of the Conservative Party does not work for people who see themselves as members of a revolutionary movement, heirs to a tradition of blood and martyrdom. The impression has been growing for months that the IRA was tired of all these complexities and wanted an excuse to go back to what it does best. Somehow Mr Major lost the script last week. His peremptory rejection of Dick Spring's proposal for a Dayton-style all-party conference - allied to the suspicion that the Tories' dwindling majority caused him to lean a little more to the Unionists - presented the terrorists with their opportunity.
Perhaps it is not too late to rescue peace, at least in Ulster. Even another dozen bombings in London might leave Belfast undisturbed - after all, the loyalists will be no more upset than the nationalists at seeing Londoners suffer occasionally what they suffered daily for some 25 years. But it is hard to see where Mr Major goes from here - any concession to the nationalists will be viewed, not least by them, as a concession to terrorism - and harder still to see where he goes if he ever gets all parties round a table. Mr Major's political wit has won 17 months of peace in Ulster, every day a small, unexpected triumph, just as it has won him six years at the head of the Conservative Party. But a larger vision is needed to find a lasting solution and it is not clear that he, or any other contemporary British politician, has that vision.