Like Paradise Lost, no-one – not even humble freelance hacks – ever wished the Scottish independence referendum campaign longer. We are, most of us, exhausted. Almost all passion has been spent. Which is just as well since, frankly, people are beginning to lose the run of themselves.

Take the ice bucket challenge. (Readers unfamiliar with social media may be unfamiliar with this. It is a fundraising challenge – originally for Motor Neurone Disease research – in which the hapless gallant stooge is soaked by a bucket of iced water. All to prove what a good egg they are. They then nominate other folk to be soaked to prove what grand eggs they are. And so on.)

Clearly this is the sort of thing that must be ruined by politicians. Just for fun and a good cause, obviously, but really to show what good sports they are. So when Alistair Darling – who does at least know a former colleague with MND – agreed to be soaked you knew it was only a matter of time before Alex Salmond would do so too. We cannot afford an ice bucket gap.

Sigh. So Mr Salmond and his deputy, Nicola Sturgeon, duly did their duty. All in a good cause, of course, even if that cause is good publicity. And, to no-one’s surprise, the SNP’s leaders decided to nominate their political opponents – David Cameron, Nick Clegg, Johann Lamont and so on. I am not sure this was meant kindly. (Ms Lamont, of course, has been dragooned into accepting the “challenge”. Mr Cameron and Mr Clegg appear disinclined to play along.) Like many fun and trivial things there was something telling about all this. Even raising money for charity, you see, can be used as a useful political dividing line. A chance to put yourself on-up and, more importantly, your opponents one-down. Sigh. Again.

Anyway, tonight’s another day and all that. Alex Salmond and Alistair Darling meet again, like twa witches on a blasted heath, at the Kelvingrove Art Gallery this evening for the second of their debates on the matter of Scotland and her future. If it is not quite their last chance to make an impact it is their last chance to make a large impact in front of a large audience. The gloves are off.

Last time out Salmond’s aides were confident he’d batter Darling. They forgot, or ignored the time-honoured convention that expectations should be lowered, not raised, in advance of any debate. So much so, in fact, that a draw would have been interpreted as a victory for Darling.

As it turned out, Darling won a comfortable victory. Which, in turn, ensures that Salmond should properly be considered the odds-on favourite to win tonight. (This is less dramatic than it sounds: in any two-horse race one nag is likely to be odds-on.) He benefits from reduced expectations just as Darling is burdened by greater expectations.

So Salmond should win, not least because it is as unreasonable to expect him to perform so poorly again as it is to think Darling will do so well as he did in their first encounter.

That’s the set-up.

But, in the end, the actual performance in the debate matters less than how the performances are perceived. Winning is in the eye of the beholder and the manner in which the bout is judged will help colour the retrospective views even of those folk who actually watched the damn thing and reckoned they could make their own minds up thank you very much.

I’m not sure the first debate really moved the polls very much and it would be a surprise – though the possibility cannot be discounted – if this one did too. Many viewers will think their guy won even if he performs like Ben Swain.

As Stephen Daisley correctly observes:

Who’s right and who’s wrong, that quaint old notion, isn’t really the point. This is now a campaign of two Projects Fear. Vote Yes and lose the pound. Vote No and lose your doctor. Salmond and Darling will not replace the names Lincoln and Douglas in the annals of elevating political debate.

Fear works. The object for the two men is not so much to refute the other’s charges as it is to scare undecided and soft Yes and No voters over to their side. We will hear the word “risk” a good deal tonight from both men. Salmond will tell us a No vote risks leaving Scotland’s NHS vulnerable to cuts from George Osborne, whom the Yes campaign has reimagined as a scalpel-wielding Thatcherite bogeyman.

Staying in the UK, he is likely to warn, also risks our place in Europe, should David Cameron’s promised referendum on membership of the EU be won by the forces of Euroscepticism. Other risk factors to listen out for: Tory majority government, Ukip, and tuition fees.

Au contraire, Darling will retort. The only risks are those we face if we vote for independence, or “separation” to use his preferred term. “Separation” will put our economy, our jobs, the very pound in our pocket under threat. A Yes vote, he will insist, is a vote to leave the EU and try to renegotiate our way in from the outside — and the same goes for Nato.

Indeed. I would be surprised – possibly even pleasantly surprised – if this proves an illuminating evening. That does not mean it will be a wasted one; the STV debate was, by the standards of these affairs, quite a good entertainment. It was certainly better – and more meaningful – than the leaders’ debates during the 2010 general election.

Still and in accordance with the traditional need to apply sporting metaphors to these tussles, this is a night for Alistair Darling to park the bus and dare Alex Salmond to break him down. That might not make for a scintillating evening but denying Salmond a clear victory is Darling’s chief objective this evening. A draw will do for him.

But it won’t for Salmond. Time is no longer his friend and though winning – and being seen to win – tonight won’t on its own swing the campaign his way another poor performance must be reckoned a set-back. He has less room for error than Darling, not least because, despite his best efforts to persuade Scots otherwise, the burden of proof remains with the Yes campaign.

I would expect – though stand ready to be refuted by events! – that Salmond will also wax more lyrical about our dreams and hopes, about how  fear is the only thing stopping Scotland being what it can – and should! – be. We can, he will say, do and be better than this. It is our moment, our opportunity, our shot at a place in the history books. What kind of people, given this kind of chance, turn it down? It’s not about Alex Salmond or even the SNP, he will say, it’s about us and the people we want to be. The idea of Scotland is a powerful thing indeed and Scotland is no lost cause at all, merely an unwon battle. We cannot afford a dream gap either.

Tags: Alex Salmond, Alistair Darling, british politics, Debates, Scotland, Scottish independence