Knowing Paddy Ashdown a little, I have no doubt that the reasons he gave for the announcement of his resignation as Liberal Democrat leader in June are both straight and sincere. The timing of the announcement may have been a more contingent matter. He probably did not plan to scupper media coverage of Lords' reform by going public on that same afternoon of 20 January. Perhaps he did not expect to make quite such a splash; he has an understated view of his own importance.
He has caught the imagination of the people, though, as a man of courage, honesty and fundamental decency. The people, not parliament - he shares that preference with the Prime Minister, to whom he is close. And he also shared with Tony Blair "the project" which, without Ashdown and Peter Mandelson, now needs to be rethought.
The project is the realignment of the centre. The elusive dream is probably one of Blair's motive forces in politics. At any rate, much of what he does and says makes sense only if one assumes it is. It is simple really: 80 per cent of Labour (new Labour), plus 90 per cent of Lib Dems, plus 30 per cent of (one-nation) Tories equals an unbeatable new constellation. The subjects around which such a project could be built were evident: constitutional reform and Europe; or perhaps the other way round, Europe and constitutional reform.
Today, this must be said in the past tense. With Mandelson gone, Ashdown going, and Messrs Clarke, Heseltine and Patten fading, the driving forces of the project have become less visible and therefore less powerful. I think that the project collapsed much earlier, and that Ashdown's departure is an admission of defeat by a man who in most other terms had a spectacularly successful career as leader of his party.
The important date was that day in late October 1997 when Gordon Brown announced, with the consent of the Prime Minister, that the UK would not join EMU for the time being. I was certainly no advocate of EMU but it seemed to me on that fateful day that if Blair was to be a great prime minister he should have had the referendum then and there. He might have lost it, though he would probably have won; and in any case this was his chance to put his formula to work: to carry his own party, to rally the Lib Dems and fatally to split the Tories. After the referendum, he would also have been free to join euroland at a time of his choosing rather than make the momentous decision the subject of an uncertain popularity contest later.
Perhaps October 1997 was also the only time to get Ashdown into the cabinet. In any case, everything that has happened since by way of co-operation between the government and the Liberal Democrats is distinctly second best, and support for it is rapidly declining in both parties. In constitutional terms, Blair cannot give the one thing that most Lib Dems really want, which is proportional representation; and a referendum on Lord Jenkins's proposals is by no means a foregone conclusion. (Referenda now reveal one major weakness: governments cannot afford to lose. Referenda are therefore only partly about the issue and largely about the popularity of the government at a brief moment in time.) The recent widening of the remit of the joint cabinet committee has neither thrilled Blair's colleagues nor revealed any distinctive Liberal Democrat policy which could become a popular issue.
Which brings the argument to Ashdown and his party. Creating an apparently stable party with a set of agreed policies and a significant parliamentary base is one of the great successes of Ashdown's leadership. Forty-six Lib Dems - who would have thought it possible when jokes were made about the group fitting into a London taxi?
Yet it is a sign of Ashdown's stature that he realised the morning after the 1997 election that this was not due to a massive and sustainable change in electoral preferences, but rather the result of a unique constellation. He therefore asked himself one question: what could he do to make sure that as many as possible of these 46 were returned to parliament the next time round? His answer was coalition - or at any rate, an opposition sufficiently constructive to continue to make it possible for new Labour voters in many constituencies to vote tactically for Lib Dem candidates.
I think Ashdown was right, and his successor will pay a heavy price if he explicitly abandons this line. In practice, however, it has already been abandoned. One reason is that the Lib Dems are in an important sense not a national party. Menzies Campbell is one of very few Lib Dem spokespeople whose voice carries on national issues. The Lords' group apart, Lib Dems find it curiously difficult to accept the national stage. They know their way in local government, in some regions (especially the West Country, Scotland and Wales), and in Europe; but they have largely abandoned the country as a whole as a political space. In this regard Ashdown is the exception: he is actually interested in national power. Many of the rest will settle for national opposition, constructive or otherwise, in order to run local councils, share power in new assemblies and have a finger in the European pie.
So Blair will have to count out the Lib Dems in pursuing his project. He also has to accept that the grand old Tory names have less resonance in the country as time goes by. Thus his formula of new Labour plus Lib Dems plus one-nation Tories is reduced to new Labour plus very little.
This need not be disastrous for the project. Party mergers, even coalitions, are high-risk ventures. Extending the range and appeal of his own party may well be the more effective option. For Blair, it may also be a difficult option; there are times when one wonders if he likes his party enough to settle for it. However, for the Lib Dems as a national force, Ashdown's departure from Westminster highlights problems of a different order. Writing the script for his successor will be an unenviable task.
Lord Dahrendorf was Warden of St Antony's College, Oxford, 1987-97