The tensions that surfaced at the weekend's Ulster Unionist Party conference testify to the forces now engulfing the party's leader, David Trimble, and therefore the hopes of a lasting peace and political settlement in Northern Ireland. For no-one should doubt that Mr Trimble's survival is essential to the preservation of those hopes. The alternatives, the collapse (again) of the devolved institutions, or the replacement of Mr Trimble by a hardline anti-Agreement Unionist like Jeffrey Donaldson, or both, stand swiftly to undo all progress of the last two years and more.

The tensions that surfaced at the weekend's Ulster Unionist Party conference testify to the forces now engulfing the party's leader, David Trimble, and therefore the hopes of a lasting peace and political settlement in Northern Ireland. For no-one should doubt that Mr Trimble's survival is essential to the preservation of those hopes. The alternatives, the collapse (again) of the devolved institutions, or the replacement of Mr Trimble by a hardline anti-Agreement Unionist like Jeffrey Donaldson, or both, stand swiftly to undo all progress of the last two years and more.

Against the bleakest possible canvas, the most encouraging aspect of Saturday's conference session was Mr Trimble's own performance, judged by close observers to be one of his best ever. The UUP leader has proved himself courageous and far-sighted before. What he has sometimes seemed to lack is a willingness to take his critics head-on. On Saturday, he showed little sign of appeasing his tormentors; instead, he showed statesmanship in underlining the importance of the Good Friday Agreement.

He may now need to go further. For, however understandable the pain felt by the Unionist community about the concessions to nationalism, from policing to the presence of two republicans on the executive, it needs to be reminded that the alternatives offered by Mr Donaldson and his supporters are really no alternatives at all.

Mr Trimble's stewardship has seen, beside a dramatic decline in violence, the historic abandonment of the Republic's claim to sovereignty of Northern Ireland and the acceptance by Sinn Fein that its constitutional status will not change without the consent of the Northern majority. Unionists have every right to be angry that the IRA has taken no further steps towards decommissioning since the inspection ofarms dumps in July. But they are making a grave mistake if they imagine that decommissioning is more likely to happen if Mr Donaldson restores Ulster Unionism to the tribalist stance from which Mr Trimble has started to rescue it.

He will need help if he is to survive the now concerted effort to undermine his leadership. By demanding 100 per cent implementation of the Patten report on policing, while at the same time ignoring the failure of the IRA to take further steps on decommissioning, nationalists may be adding to the dangers. But most of all, it falls to Mr Trimble himself to say to opponents and supporters alike that, by sacrificing him they are also sacrificing the hard-won gains of the peace process. Mr Trimble is not merely fighting for his own political life. His fight is to keep Northern Ireland on the road to the decent civic society for which its people, deep in their hearts, must still yearn.