In politics, momentum is everything. And loss of momentum is a frightening thing for those once possessed of it.
But there is no more ready way to lose momentum than to be frightened of that very occurrence.
In the run up to the Democrat Primaries in 2008, all of the momentum was with Hilary. She was the presumptive nominee before a single vote was cast. She was the first truly credible woman candidate for the Office she pursued. She inherited an aura of competent economic management from her much regarded spouse. She had shaken the hands and done all the deals that were meant to matter. But, fatally, she decided that the best way then to maintain her momentum was to do nothing. To avoid losing any votes she already thought she had by scaring them off in pursuit of further support.
And then Iowa voted. In some ways it was heroic the way she carried on. Indeed remarkable the residual support she continued to attract. But she could never really get her momentum back. The rest was just process.
Now, it was said of Blair in the run up to 1997 that he was in the position of a man charged simply with the task of simply carrying a ming vase across a crowded room. But, even I , as one of his fiercest critics, recognise that he did much more than that. He did not simply maintain his momentum, he accelerated its pace. Success, he gambled correctly, would not come from slowing down and getting there eventually but by speeding up and arriving at the destination with time to spare.
So, from a sort of detached perspective, I can understand the dilemma which faced the SNP today.
It's all very well to point out that the problem of appearing to want to maintain their momentum for a further 29 months would be, if they actually intended to have a referendum, a problem of their own making. But it is a problem nonetheless.
No matter how they spin it, they know that the Local Government Elections were a reverse. It wasn't just that they failed to take Glasgow, once you look at how the coalitions have settled out, there are an awful lot of places where they used to be in power where they are in power no longer. Not least in my former Renfrewshire stomping ground.
So, today's date having been in too many diaries for it to be quietly called off anyway, any hope of maintaining an already slowed momentum, demanded that they go ahead.
Some of what then went wrong was beyond their control: Anybody planning to go to a cinema at ten in the morning on the hottest day of the year was bound to appear a bit eccentric but the weather could hardly have been predicted; Sir Sean was clearly meant to top the bill and even I don't think his non-appearance was likely to have been because of waning enthusiasm; a rally weeks in the planning inevitably takes a risk, in this case particularly jarring, with appearing to be hpoelessly out of tune with immediate events elsewhere.
Some other problems might have been anticipated at least to a degree, most obviously something like this morning's poll, the results of which, although hardly unexpected, nonetheless seemed to leave normally articulate performers floundering for an explanation.
All of that having been said, the event was, on anybody's view, a bit ............naff.
There are reasons people gave up on Old Labour. It was a great institution in it's time but it's time has gone. Those of us opposed to the "New" variety didn't object to change, just to the type of change. The kind of male dominated, heavy industry, politics of Dennis Canavan and Tommy Brennan (both of whom remain people for whom I have the highest regard, even affection) belongs over a nostalgic pint in the Miner's Welfare, not as some kind of template for a supposedly modern, Scandinavian style, Scotland.
And Dougie McLean wrote a great song, but that kind of lachrymose, here's tae us, wha's like us sentiment is also something that makes not just me but a significant sector of the middle ground more than slightly nervous that this whole project represents a triumph of romance over reality.
And then we had the rather Begbiesque rant by Brian Cox. If you want to rely on celebrities you surely don't let them write their own scripts and, even if you do, you at least check out the accuracy of what they intend to say about their personal history.
Much has been made about the lack of women, or ethnic minorities but, also, where were the young people? Something even I concede is one of the Nationalists strengths.
All in all you were left with the impression of an event focussed on wrongs done to Scotland in the past, often supposedly by the Labour Party, rather than an event focussed on a brighter future.
But I finish where I started. There clearly was felt to be a need to have some sort of event. But there was also a desire not to scare anybody's horses. The result however was not to gain momentum but to continue to lose it.
There's big trouble brewing for the SNP. Salmond clearly wanted to be able to give the impression, when eventually calling off the vote, that he might just have won. And he certainly wanted to maintain some uncertainty on the point for as long as possible. No wonder he was crying at the end.