It's possible that I misunderstood the job description.

Perhaps I failed to grasp that a prime minister of Great Britain and Northern Ireland doesn't always seize the chance to defend the state in every circumstance, not least when it faces an existential threat. But then, mercifully, I am not David Cameron.

We all know perfectly well why the PM will not risk a televised debate with Alex Salmond on the issue of independence. Cameron knows he would lose. He knows, moreover, that the urge for self-determination has a lot to do with the party he represents. He knows that his command of the facts is sketchy. He knows that Salmond is skilled in debate. As a Tory predecessor once put it, in the patois of her childhood, Cameron is "frit".

The First Minister, in turn, understands all of that perfectly well. He knows, too, that framing the argument in terms of heads of government helps to complete the SNP script, as though to say that a kind of Scottish autonomy is already an established fact. Salmond desires a perfected symbolism. He speaks for Scotland; who speaks for Britain if its primus inter pares will not exert himself?

We were led to believe, not least by the MP in question, that Alistair Darling was up for the job. The chairman of - what's the latest name? - No Better Thanks let it be known, repeatedly, that he would submit to a televised circus "anytime, anywhere". That apparent guarantee has worn a little thin. Salmond would debate with Cameron on July 16, but can only find time for Darling in early August, when the Commonwealth Games are done. The Unionist campaign therefore redefines both "anytime" and "anywhere".

So be it. Portray STV as a victim of the Salmond jackboot. Throw an obliging BBC into the mix as a preferred alternative broadcaster. Muddy the waters as only Better Together, dodging debates in every town and village in Scotland, can. But then explain it: just why is Alistair Darling acting as a hapless human shield for David Cameron? If the Union needs defending, surely it has at least one prime minister worth the name?

These TV debates are worthless, of course. Witness only what has become of such celebrity death matches in the United States, where long days pass while lawyers quibble over how their candidate should be lit, far less understood. Anyone who believes that British democracy was improved in 2010 while everyone agreed with Nick might have misunderstood the participative ideal just a bit.

"The people" are reduced to "the audience" - that's not good. In the context of an unparalleled popular movement such as the Yes campaign, it is downright pernicious. I can't be the only person determined to vote for independence who is liable to feel slightly at odds with everything Salmond might have to say. I know perfectly well, equally, that there are people devoted to Britain who look at Cameron and Darling and think: "None of the above." A TV debate is a caricature.

Nevertheless, since the Prime Minister refused to allow room for nuance on the ballot paper, this is where we are. Each side grapples for advantage. Each side wants the broadcaster that suits best, at a moment that best suits the campaign wallchart grid. Each will have teams of prose stylists crafting their soundbites.

This is party politics. It isn't good enough for the average electoral contest; it is horribly, insultingly wrong for what is taking place across Scotland in this benign and hopeful summer. There are people who will vote Yes who would be appalled to be called nationalists. There are people who will vote No who cringe at Cameron and all his works. There are many others besides. There is an insult, implicit and explicit, in TV's conceit that it might all come down to Alex and Alistair.

We are no longer an audience. No version of journalism, broadcast, print or online, has quite captured the fact, as yet. Those who pay lip service to the notion of an engaged and informed electorate still don't care for the reality. Democracy doesn't happen on TV. Arguments are not resolved by the intercession of a skilled moderator, or nudged by a so-called "opinion-former". This is not "a campaign". This is a discussion within a community. And we're getting good at it.

Better Together seems to find the fact uncomfortable, in my partial opinion. The control freaks freak out over the nuts and bolts of a TV debate - or any sort of debate - and forget how their self-involved, hair-splitting language is understood back in reality. Inside the bubble, the world beyond grows dim. But what voters remember is simple: "Anytime, anywhere."

Cameron has not managed to summon even those two words. This ought to give his backers pause. The PM excuses this behaviour as non-interference in the affairs of a country that is not, it turns out, the business of a man who heads the government of Great Britain and Northern Ireland. Were I a Unionist I would be demanding an appearance, front and centre, from Cameron. But up here in the outlands, we are supposed to know - by instinct? - why such a thing is unthinkable.

He would lose. Why is that? The question is serious. If Cameron had a story to tell, he should be relishing the fact. He should not be allowing Scottish Labour to twist its remaining guts into tiny knots just to save a Tory premier from queering the Unionist pitch. If Alex and Alistair get their diary issues resolved, the question will hang in the air: Where's the PM of that great country of yours?

Scotland's contempt for the Conservative and Unionist Party has been talked down somewhat. Didn't they get a handy quarter of a million votes last time? Don't they therefore retain the right to lecture us on everything from council house sales to land reform? Not really. Were it not for that touch of proportionality in voting they elsewhere abhor, they wouldn't exist. Yet they seek to manipulate a country's future through the agency of an individual who refuses to make a case on TV.

Instead, Cameron has Scottish Labour as his serving staff for that kind of tedious thing. When next someone communes with "the English Left", it might be a fact worth mentioning. A Labour Party that serves as a Tory front might just be beyond saving. When Salmond gets his chance, he will no doubt mention the fact. Darling will no doubt grow vehement in his denials. The rest of us will probably wonder what else is on. A talent show would be fun.

Sometimes you get the chance to notice history while it happens. Salmond dodges and weaves, as ever, but Cameron just hides. Darling says "anytime, anywhere", but what he means is "not here" and "not now". If that's the best case for the most successful union ever imposed on a country, you would hate, I think, to see the worst.