A FRIEND who happens to be one of Alistair Carmichael's constituents is slightly dumbfounded to hear the new Secretary of State for Scotland described as a tough bruiser.

By what process has the genial, well-liked and diligent MP for the Northern Isles been transformed?

Michael Moore would probably have an opinion, but Berwickshire's man isn't saying much, for now. If you believe the instant spin, he was deemed to have come off worst in a debate with Nicola Sturgeon - for who has not? - and was sacked for a lack of "toughness". The word is supposed to set the tone for the months ahead.

But why is that? Much of the Unionist chatter holds that the game is already done. The self-validating logic of opinion polls decrees that Scotland has made up its mind. We will reject independence next September: the deal is done. Why sack a Secretary of State on that account?

It might be that Nick Clegg needed a post to trade and picked on the least contentious job he had available. That would lend a certain perspective to the claim that the Union is of utmost importance inside the Westminster bubble. If the leader of the Liberal Democrats doesn't think much of "Scotland's man in the Cabinet", the rest of us can form an opinion.

The contrary view, promoted from the instant Mr Moore was dismissed, maintains that the gloves are coming off. Emollience, in this version, will no longer do. Labour will put up Jim Murphy - not demoted in the slightest - to press shoulders with Mr Carmichael and Alistair Darling. Tories will be provided discreetly, as required. And as the new Scottish Secretary has remarked, no nonsense will be suffered.

It doesn't quite amount to an argument, but such is the Westminster way. All will be "tough"; nationalism in all its hues will be exposed as nonsense. Rigour (and Jim Murphy) will be brought to bear to convince Scots once and for all that there's a pig in the poke. Fair enough. We can look forward to invincible logic.

It all tends to say, nevertheless, that previous efforts have been found wanting. You might almost conclude that the ad hoc Unionist partnership is not wholly confident. If this is simply a stratagem to keep David Cameron out of the game, it is elaborate indeed. And a small detail: it won't work.

The suggestion is, presumably, that Mr Carmichael will say everything Mr Moore has been saying, but say it better, with more eloquence and force. Nationalism will henceforth be rebutted with more haste. No quarter will be given from the new, tough boys in the constitutional debate. What is this? Sharks and Jets?

What it is not is an attempt to give the voters of Scotland the respect to which they are entitled. If the demand is for facts, why has Michael Moore failed in his obligation to deliver those treasures? If the call is for serious, mature and honest discussion, where does "tough" come in?

Again, the supposed state of play is pertinent. Aside from some weird movements in the No vote, those polls are supposed to be definitive. In Unionist terms, the claims made for independence have been refuted. Yet here's Philip Hammond, the Defence Secretary whose sole claim to fame is the sacking of defence personnel, turning up again to say that in the event of a Yes vote I won't get my own tank.

That's a pity, for several reasons. But let's give Mr Hammond credence on his own terms. He calls the SNP's defence plans "insultingly vague". Presumably, the possible uses for a renewed Trident system are crystal clear. Still another Ministry of Defence analysis, while forgetting to advocate the annexation of Faslane, says that national security might cost Scotland - I paraphrase - "a bit". In comparison with what we pay already?

I misrepresent the purpose of the exercise, of course. In Westminster, it's all hands to the pumps. The pretence is that a case must be made for the United Kingdom. The reality, over and over, is to sow those little seeds of doubt and fear. On Mr Hammond's watch, that means troubling Scots who worry about defence jobs and our ability to repel some invader he cannot quite name. Nevertheless, the theme remains the same.

It would be nice to affect surprise. Instead, the excitement comes from wondering what they'll come up with next. Personally, I'm giving 5/1 on famine, but that's neither here nor there. Why sack a Scottish Secretary when the predictable scripts have been written? Why trumpet "toughness" when the polls are so favourable?

You might have thought, in fact, that we would now be hearing about all those long-promised schemes for the improvement of devolved government. You might have believed that the new, enhanced benefits of Union would be advertised loud and long by that nice Mr Moore. What could possibly go wrong with a positive case for partnership?

Such is not the selected strategy. Even if you have yet to begin to think about a referendum choice - and who could blame you? - the fact is striking. By all accounts, Alistair Carmichael is a well-liked and attentive local MP for islands that need all the representation they can get. Yet overnight, an affable man is turned into a Unionist terminator. Let's call that a little crass, shall we?

Let's also notice what these games appear to represent. Above all, they show an understanding on the No side that the game is far from over. Alistair Darling, smart man, has said as much repeatedly. He has a lot of anecdotal evidence, the kind the pollsters despise, on his side. If the game was truly won Unionists would, in the parlance, dial it down. That's very far from the case.

So what should we understand by all the tough talk? Attacking Alex Salmond and Ms Sturgeon would be customary, referendum or no referendum. Occasional speeches on the dream of Britishness would be the least of a taxpayer's sufferings. But if Mr Carmichael is a bruiser, bruisings should follow. That sounds exciting. It sounds as though we are in for lurid rhetoric.

I offer Unionists the advice gratis: that's not a good idea. If the UK is benign and beneficent, sensible and wise, it ought to be capable of better than that. Awakening slumbering fear does not often pass as "positive". Telling us what we already know about old relationships is not enlightening. But, by all means, be my guest. You can shout "Boo" now and then, if it helps.

It will be a pity if grown-ups decide to turn this argument into a children's party game. This is not puerile, as yet. But if someone has decided that the best defence of an old Union is acting tough, I question seriously the education acquired by such folk. Seriously, I question what they think they know of Scotland.

In an odd way, Nationalists ought to be flattered. London remains nervous. In another sense, it's a bit of an insult. Those opposed to independence still do not understand the rational case, far less the emotional impulses. They have not bothered to understand.

That is, of course, one reason why the demand exists.