In “Painting Nationalism Red?”, an engaging new pamphlet published by Democratic Left Scotland, the journalist Neal Ascherson pays tribute to Tom Nairn as Scotland’s “pre-eminent political intellectual”.

The theorist and academic, best known for his 1977 book “The Break-up of Britain”, has indeed exerted an enormous influence over the British Left – nationalist and non-nationalist – over the past four decades.

Nairn eloquently charted a “delayed” shift in Welsh and Scottish nationalism from devolutionary self-government to possible full independence, something he memorably described as “Janus-faced”, combining elements of what later became known as “civic” and “ethnic” nationalisms.

While there is much to recommend The Break-up of Britain, its central contention that the UK’s archaic unwritten constitution was approaching collapse hasn’t aged well. For all its faults, the Union has survived, enduring the Great Financial Crash and two referendums. Nairnites tend to skirt over this weakness, confident he’ll eventually be proven correct.

Take SNP MP Pete Wishart, who’s recently been churning out thought pieces which are sadly devoid of much original thinking. “Scotland will secure its independence and we are so tantalising close,” he wrote last week, “but we have work to do in convincing our fellow Scots who voted No last time to join us.” Well, quite.

Such thinking – that the benefits of independence are so self-evident they don’t require articulation – continues to stymie the independence movement. Wishart et al view it predominantly in tactical terms, thus their suggested “roadmaps” to victory contain little or nothing about economics and lots about “timing”.

Wishart even retreats into tartanry of which Nairn would surely disapprove, invoking Mel Gibson’s “Braveheart” in order to urge his party to unleash its referendum “weaponry” at the “optimum time for success”. This, he contends, requires “a new independence offering” that reflects “the Scotland we now live in”. It also needs to be “persuasive”, but details come there none.

Rather Wishart believes No-voting Scots will eventually take “renewed interest” in the “constitutional lifeboats strapped aboard the doomed HMS Brexit UK”. But the central problem with this analysis remains unchanged: rather than offering a “lifeboat”, the current independence proposition resembles another Brexit-like leap into the unknown.

Optimists presumably hope Andrew Wilson’s Growth Commission will rejuvenate the independence case ahead of a second referendum, although obvious nervousness at publishing its recommendations speaks to misgivings among the party leadership (ie Nicola Sturgeon) over any move beyond Alex Salmond’s failed strategy of “independence will make everyone rich”. It seems there’s only so much realism the faithful can handle.

Thus even the Common Weal think-tank, which has made admirable efforts to set out an alternative “White Paper” (which Wishart now regards as an “historical” document), ends up body-swerving obvious weaknesses rather than tackling them head on. Its latest proposal, for example, is the creation of an “independent” Scottish Statistics Agency that’ll put the annual GERS bun fight to rest.

Where to start? While Common Weal makes a reasonable point about the quality of economic data, it also implicitly buys into the view of GERS as a fundamentally flawed and even politically skewed set of figures. This necessitates the usual reality check: not only is GERS produced by the Scottish Government (which was run by the SNP when I last checked), but over the past decade its methodology has been extensively improved, including a geographical share of North Sea oil revenues, and so on.

In spite of all that, it continues to show a sizeable (and, yes, notional) fiscal deficit, so the idea a new set of figures produced by a new statistical agency is going to alter that central point is for conspiracy theorists and dreamers rather than anyone with a rational grip on political and economic reality.

Once upon a time, Nicola Sturgeon made a lot of speeches which appeared to be softening up her troops for a more realistic independence proposition than that rejected by a majority of Scots in September 2014. This looked promising, but (typically?) there was a conspicuous lack of follow-through. After June 2016 she and many others succumbed to the superficially plausible idea that the case for independence was now beyond question.

Indeed, the sterility of the independence debate over the past three and a half years stands in striking contrast to the hopes and aspirations vested in the movement’s once-idolised leader. There are, to be fair, exceptions. Julie Hepburn, a new contender for the deputy leadership of the SNP, has stressed the need for “preparation” and “listening to No voters” over fruitless Wishart-like speculation as to the timing of a second ballot.

Even more refreshing was a recent article by musician Ricky Ross, a prominent figure in the independence movement a few years ago. He confessed to having reflected upon his “strident declarations” over decades of campaigning and whether others had actually heard what he thought he’d been “trying to communicate”. Invoking Woody Guthrie, Ross wondered if it was time for everyone to “ask a different question” rather than taking an unequivocal “side” in the constitutional debate.

In an impressively cogent speech at the David Hume Institute last week, Scottish Liberal Democrat leader Willie Rennie made a renewed plea for such an approach. A federal solution, he argued, would allow the UK’s different administrations to pursue “different priorities” while retaining “an eye and a care for the success of the whole”. The SNP’s Nairnite belief in the impossibility of UK-wide “success”, of course, makes that difficult if not impossible, but it doesn’t mean it isn’t worth trying.

Indeed, parts of Tom Nairn’s seminal 1977 book read more like a plea for federalisation of the UK rather than full independence for its component parts, as if even he believed there was life in old “Ukania” yet. Unionists, as ever, are missing a trick in not filling the intellectual void at the heart of modern nationalism with a vision of their own.