It is important to say it now - it is not all over. David Trimble achieved a highly satisfactory result in Friday's Northern referendum. He will be strengthened also by the massive determination in the Republic to drop the territorial claim. With 71 per cent support, the Belfast Agreement has achieved a local legitimacy always denied to Sunningdale. It is said that when the then incoming British prime minister, Harold Wilson, saw the anti- Sunningdale unionists take a majority of the Northern Irish vote in the 1974 general election, he mentally wrote off the powersharing executive. This is, indeed, in part the clue to the British government's apparent indecisiveness during the power-sharing executive's final crisis. This time the rejectionist force of unionism has not even managed to win a majority within unionism let alone the people of Northern Ireland.
This fact alone gives the initiative to Mr Trimble. The men in the grey suits referred to by dissident Ulster Unionist MP, Willie Thompson, will not be coming for Mr Trimble this week.
Indeed, despite the loss of more than half his parliamentary party, Mr Trimble has retained the support of the great majority of the Ulster unionist electorate in the country. The most important of the No voting MPs, Jeffrey Donaldson, has signalled that he has heard the voice of the Northern Irish people. Mr Trimble, therefore, has the initiative. But he also still faces significant problems.
Most seriously, the UMS/RTE exit polls which got the result right reveal an Ulster Unionist Party apparently becalmed at 19 per cent support, flanked on the one side by the Alliance at 9 per cent - which is perhaps suspiciously high - and the UK Unionist Party of Bob McCartney at 7 per cent. There is a sign here that Mr McCartney - for all that his own constituency appears to have supported a Yes vote - has a definite appeal to Ulster unionist voters who are disturbed by the agreement. The DUP retains a support level of 13 per cent. This places the total anti-agreement/ unionist party support at 20 per cent, while those unionists parties supporting the agreement are on 24 per cent - the PUP has 3 per cent and the UDP, 2 per cent. This is too close for comfort; the assembly's proper working is predicated on the unionist community electing a majority of representatives prepared to accept the spirit of the agreement. On present showing, Mr Trimble and his allies are likely to be able to do this but it will be a closely fought contest and nothing can be taken for granted.
Mr Trimble has other problems. A week from the end, the Yes campaign was on the verge of losing large segments of the Protestant middle-class which had initially reacted favourably to the agreement. The campaign was in serious difficulties, with a mediocre result in prospect.
The critical issue was the early release of paramilitary prisoners; in part, because it offended a public sense of morality but, in part, because it raised fears about the future. Was the day of the men of violence and the threats of violence really over? Here Mr Tony Blair's intervention was crucial. The Prime Minister's reassurances won back the Protestant middle-class. However dreary it might be for Mr Blair, this group of conditional Yes people will continue to claim a lot of his attention before all this is over.
But the graphic fears on such issues are not Mr Trimble's only problem. More worryingly, the poll evidence suggests that a lot of unionists simply do not understand Mr Trimble's areas of negotiating success. They do not see the significance of the new British/Irish Council, designed to enhance linkages between the devolved assemblies of the UK. They do not still appreciate the importance of the removal of the territorial claim - after all, an acceptance by Irish nationalism of the legitimacy of British rule in the North. They do not see how he has achieved a model of cross-Border co-operation which is non-threatening.
This is frustrating for Mr Trimble. Many observers feel he did a good job in the talks on such matters.
Mr Trimble has not exactly lost the argument on these points but neither has he won it. In the next few weeks, he has to hope that the electorate is more reassured by his vision. He has a real chance of success - most unionists want any assembly to work properly and they will be reluctant to return wreckers. But they can be provoked and if their concerns are disrespected, they will do precisely that.
In the longer term, the future of Mr Trimble's unionism will depend on republicanism. One of the neglected clues to Mr Trimble's success in remoulding unionism lies in the assumption of some of his younger followers that they have nothing to fear from the arguments of Sinn Fein. Deprived of the historic greviance of Partition and British rule by the voice of the Irish people in a referendum, what is it exactly Sinn Fein has to say when the arguments get tough? There is still the "equality" agenda but, it has to be said, fear of the equality agenda seems to have motivated very few unionist voters on Friday. If republicanism continues its current breakneck pace of revisionism it can expect engagement with a more self confident unionism very shortly.
Such an engagement is a necessary part of the "normalisation" of Sinn Fein, which must occur if Northern Ireland is to have stability. As Mr Trimble has long recognised the principle of proportionality - also long accepted the likes of Lord Molyneaux and Ian Paisley - means that Sinn Fein cannot be denied their own share of local pomp and circumstance. But for ordinary unionists to live with this, they have to feel that the threat of violence has gone for ever. But, they also have to feel that Sinn Fein has lost the political initiative, in the sense of maintaining a relentless drive towards Irish unity. Only a direct and authoritative unionist engagement with Sinn Fein can provide that reassurance. It is also necessary, of course, to remind people of the strength of the centre - Mr Trimble and John Hume together became a potent image in the last few days of the campaign. If people believe that there is a coherent common SDLP/Ulster Unionist Party programme of government, they are likely to rally to it.
Paul Bew is Professor of Irish Politics at Queen's University, Belfast.
The leader of the Ulster Unionist Party, Mr David Trimble, at the referendum count in the King's Hall, Belfast, on Saturday. Photograph: Frank Miller