The UK is about to enter a period of acute political uncertainty, after several generations of relative stability.
If Scotland votes No in September, this will give David Cameron a fillip and he will be able to go into the UK general election next year claiming that the UK has been kept intact under his watch. That, and the performance of his Chancellor George Osborne, might well be enough to provide them with a victory. If so, that will settle little, for the whole of the UK will immediately be plunged into an exceptionally bitter battle over Europe.
Mr Cameron must regret his promise of a referendum on the EU, following a dubious process of "renegotiating" Britain's membership terms, but he cannot wriggle out of it.
The campaigning that would precede this referendum might be well be the most visceral and vicious political battle fought in Britain for many years. It could tear the Tory party apart, even destroy it.
The previous referendum on British membership in 1975 is hardly a pointer to what will happen. That was a genteel, somewhat boring affair in which many politicians discovered that they quite enjoyed making common cause with like- minded folk from other parties. The result was an impressive victory: well over 17 million voters endorsed UK membership, with their opponents unable to muster even half of that total.
It could be so different this time. The divisions, not just within the Tory party, are rancid. Indeed much of England, if not Scotland, loathes the EU. Yet the hatred for the EU that now festers in much of the Tory Party, which is still the pre-eminent political party in England, remains largely beneath the surface. Once fully unleashed, it will make Nigel Farage look like a meek and moderate man.
In this particular scenario, Scotland would not necessarily be facing a clear and settled future, for even a decisive No vote this September will not make the constitutional issue disappear. Far from it: there would be a lot of manoeuvring about how to strengthen and improve the devolution settlement. And I'm certain that another referendum would be held before too long, particularly if Westminster descended into extreme strife, which is more than likely.
The ongoing revelations about the louche and fetid culture (to put it tactfully) within the Palace of Westminster indicate just part of the problem. The Victorian politician John Bright called England the mother of parliaments, but many since have hijacked the phrase and described the Palace of Westminster as the mother of parliaments. That mother is now a pretty sick old crone. To continue the analogy Holyrood, by comparison, is an exemplary young woman.
Of course she isn't perfect, but in most respects she is superior to the much older and allegedly more venerable lady in London.
Meanwhile if Scotland votes Yes in September, that is obviously not going to provide much short-term certainty, in either Scotland or the rest of the UK.
I'm sure that Scotland would enter the prolonged and complicated negotiations that would ensue in a spirit of goodwill, and I also reckon that the rest of the UK's Government - although its composition might in due course change - would try to do likewise.
But the negotiations, over 18 months or more, would be bound to be a time of very considerable volatility.
Many people - particularly businessmen - tell me they detest uncertainty. I'd have thought good businessmen - or good entrepreneurs, anyway - would thrive on uncertainty, but there we are. The certainty that the UK has had for two or three generations has brought little but stagnation and decline.
This is certainly true economically and financially; it may be less so socially and culturally, but I think that few people could claim that today's UK is a vibrant, forward looking and socially just society. Many, possibly most, of its voters tend to be disillusioned and cynical.
It is altogether to the good that everything is about to be shaken up, but the process will not necessarily be easy, smooth or pleasant.