Robertson says Scotland could "share bases, procurement and training facilities with the rest of the present UK… in exactly the same way as defence co-operation exists across the Scandinavian nations." His political opponents have lined up to disagree.
Shadow Scottish secretary David Mundell says: "Alex Salmond can't expect to break up Britain and have the rest of the UK dance to his tune." A Labour spokesman describes the plan as "complete fantasy", and even online nationalists are worried that sharing military resource will simply drag Scotland into "English war mongering" all over again.
So far, so predictable. But think north and east instead of south, and a more radical, constructive alternative awaits. Beyond the endless argument about the relative merits of devolution, Calman, fiscal autonomy or independence; beyond the cross-border insults about Trident, shipyard jobs and aircraft carriers; beyond the present mathematical impossibility of a referendum vote at Holyrood, lies a path towards lasting social change. Scotland could apply to join the Nordic Council. Today.
The governments of Sweden, Norway, Finland, Denmark and Iceland formed the Nordic Council after the Second World War to promote co-operation. There are no childish grudge matches, even though some members were unwillingly run by some of the rest – in Iceland's case as recently as 1944. Members also include smaller near-autonomous island groups like the Faroes, Greenland and Aland islands. There's been a common labour market for half a century and free movement across borders without passports. The Nordic Council has helped develop a highly successful Nordic way of life across five separate sovereign nations.
Why should Scotland seek to join? Firstly, almost every policy proposal from the SNP is currently a straight lift from Nordic practice, but sometimes an unwitting and highly selective one. Extracting policy success without also importing its social and political context may simply fuel frustration. The prisons reform policy of the Finns, for example, may be the right way forward for Scotland, but transplanted from the rational, evidence-based society of Finland to the judgemental emotionalism of Scotland it may wither in the cauld blast of knee-jerk oppositionalism that passes for debate here.
Scotland is moving naturally towards the same general policy of neutrality observed by all modern Scandinavians nations. Closer involvement with experienced neutrals could only help Scotland evolve a new defence strategy, fully aware of the benefits and pitfalls of shared and scaled-down defence arrangements.
Secondly, after a UK party conference season that has ended without the delivery of a big idea or new sense of direction, Scots need more than a series of proposals. We need a new direction of travel that is not dependent on a single (and currently unlikely) piece of constitutional change. The Scandinavian model could produce a new sense of purpose and direction.
Thirdly, exposure to the rational Scandinavian decision-making style could help Scotland grow up. We urgently need mature policy debate unhampered by constant comparison with England, or the distortions of sectarianism, sexism, and second-best.
Nordic nations already share facilities and control. Denmark and Sweden are creating a new cross-border super-region which may shift the heart of Sweden from Stockholm to its pre-independence locus opposite Copenhagen, thanks to new human dynamics created by the Oresund Bridge.
Finally, membership of the Nordic Council offers a way out of its current hubris for the SNP leadership. Scotland needs to learn – every nation does – but the need to raise levels of self-esteem in Scotland is producing a dangerously "wha's like us" attitude that is verging on outright arrogance. Wha's like us in size, natural resource base, northern latitude and chequered constitutional career are the membership of the Nordic Council. Each has risen in a century from brutalising poverty to world-beating success, experiencing prosperity through – not despite – a common emphasis on equality, compromise, environmental protection and innovation.
If the Nordic Council isn't the right nursery for a fledgling Scottish state, or a more fully devolved national region, I don't know what is.
There is a problem though. Scotland isn't a country. This may or may not be an insuperable barrier. Veteran Scandophiles believe influential Swedes and Danes have been open to the notion that Scotland could seek to join. My own more recent travels and conversations in Norway and Sweden suggest the high-handed behaviour of SNP ministers could be endangering that prospect. Diplomats of both countries recount cancelled events, lectures about Scottish independence preceding meetings and a baffling lack of awareness from leading members of an independence party that Scotland is not actually independent.
Nordic states do not regard Scotland as an equal because she is not. If the SNP can get over this fact, we could all move beyond superficial debate about arcs of prosperity and insolvency and cultivate new friends in Scandinavia as well as old ones in the American diaspora. International diplomacy SNP-style is too often like being whacked in the face with a banjo. This can change.
Turn the map of northern Europe on its side, and you can see a new geography for Scotland. Routes of a Viking invasion a thousand years ago now lead to a new Nordic future – if we have the courage and humility to ask to join.