It was a measure of Mr Blair's skill, then, that he was able to deflect the Eurosceptic charge so effortlessly, and to present the crisis as an opening for reform. It was his good luck, too, that the German chancellor, Gerhard Schroder, just happened to be in Downing Street the next day, allowing Mr Blair to present the drive for change as an Anglo-German initiative.
But it is also true that the British pro-Europeans are especially well placed to lead the charge. In so many Continental countries the underlying case for the EU is so taken for granted that its institutions are rarely questioned. In contrast, the bitter debate in this country has consistently forced the pro- Europeans here to defend the EU from first principles. This newspaper, for example, yields to no one in its support for a united Europe, and yet we have consistently argued that Europe needs a new constitution to make its supranational government democratic and accountable. But written constitutions are only as good as the political culture which operates them, and such cultures tend to be forged in moments of crisis. This is hardly the European Parliament's Glorious Revolution, but it will undoubtedly be a more powerful body in future than in the past. That can only be a good thing, for the more Commissioners are forced to explain themselves and sell themselves to the people of Europe, the better.
The Prime Minister's opportunism in using the crisis to open up Europe's executive is to be warmly welcomed - this is opportunism not in the usual sense of seizing opportunities without regard to principle, but of exploiting events to advance a principled cause.
Such principled opportunism is just as needed elsewhere, after a week in which Northern Ireland threatened to slip another couple of notches back into the pit of pain and despair. While we acknowledge the grief of the bereaved, there is a thread of hope left hanging after the killing of Rosemary Nelson, as after the Omagh bombing, which is that neither atrocity prompted retaliation.
Mr Blair, the rigorous opportunist, knows that an imperfect ceasefire is better than an all-out terrorist war. He knows that a rigorous stand on the issue of the IRA handing over its weapons would have ensured that the current ceasefire was never declared. All the same a government that continues to free terrorists - to the accompaniment of the sort of disgusting scenes we witnessed in Belfast on Friday - must press more urgently than ever for decommissioning. There has been a lot of give by all sides in this dispute, but there has also been a lot of take. Sinn Fein/IRA must give more. And yet to yield to despair - or, as some would wish, to cancel the Good Friday agreement in the name of notional justice - would result in more misery, more death. For all the three steps forward, two steps back, it is better to have set out on this road than never to have tried. It is in that spirit that the challenges of imminent deadlines, negotiations and Orange marches need to be faced.
The real business of progressive politics is always compromised, unpredictable, and difficult. Fixed ideas are no help in the post-ideological, post-Cold War world. What that world needs is the politics of principled opportunism.