“Great Britain has lost an Empire” was Dean Acheson’s famous observation in 1962, “and not yet found a role.”

A put-down from a former American Secretary of State infuriated the British political classes largely because it was true. At that time the wind of change was blowing across Africa and the United Kingdom was trying to fashion the Commonwealth into something more than an annual photo-call.

But to Acheson, this attempt to play “a separate power role” apart from the then European Community and based upon a “special relationship” with the United States was “about to be played out”.

He was right, and in the decade that followed the UK belatedly attempted to join the European club, and after 1973 managed to balance somewhat grudging membership of the European Union with a largely mythical “special” relationship with the United States.

That, as former First Minister Alex Salmond remarked in the House of Commons last week, was a “rational, logical policy”, but of course the events of 2016 have ensured that it too is about to be played out, replaced by an Anglo-American alliance symbolised by Theresa May literally walking hand in hand with Donald Trump.

Much of this is a nostalgia trip, a hankering in both countries for a magical golden age in which each played a leading world role. As Mr Salmond also said, some Tory backbenchers seemed unreconciled to the “empire bit” of Dean Acheson’s famous aphorism, otherwise there’s lots of quixotic stuff about trade. But as the former chancellor Ken Clarke put it in the same debate, many of his colleagues seem to have emerged in a “wonderland” where countries like Turkey and the US are suddenly “queuing up to give us trading advantages”.

At least – and I’m trying hard to find a positive in any of this – how the US and UK perceive their role in the new world order is a little clearer after months of uncertainty (and May, to her credit, did manage to shore up Nato on her US trip). What’s interesting is where this leaves Scotland which, as Nicola Sturgeon regularly asserts, is now compelled to choose between remaining part of Brexit Britain or carving out its own role. Or, as SNP press releases now frame it, choose between “Trump-style isolationism or progressive politics”.

During the last referendum (and it now looks increasingly likely there’ll be a second) Scotland’s possible role in the world rarely progressed beyond vague idealism and platitudes about being a “guid neighbour”. Nationalists often articulated a rather naïve view of geopolitics in which everyone would be nice to a newly independent Scotland because they liked its history and scenery.

Speaking in last week’s Brexit debate, Mr Salmond showed little sign of having moved on from this sort of stuff, still burbling on about Sir William Wallace writing to the Hanseatic League in Lübeck. “The importance of Scotland’s European connections stretches back a millennium,” he declared, “and we are not going to allow this non-vision…to take Scotland out of those connections.”

But, as ever, the SNP’s own “vision” appears highly flexible. Salmond was recently quick to deny that the party leadership was preparing to downgrade “independence in Europe” to “independence in the European Economic Area” (try selling that on the doorstep), but it was clearly testing the water with newspaper reports to that effect. Such a shift would make a lot of sense – it’s both more realistic and politically useful in terms of keeping hold of Yes/Leavers – but it’d hardly be principled, not least because the whole rationale for a second independence referendum rests upon Scotland being “dragged” out of the EU against its will.

Usefully, the academics Michael Keating and Malcolm Harvey explored various options in a book, “Small Nations in a Big World”, published while Brexit and Trump were still a right-wing fantasy. They argued that small states like Scotland could do well in the global market place, but had to make a choice about how they faced the world.

Some, such as the Baltic states and Republic of Ireland, have accepted market logic and taken the “low road” of low wages, low taxes and light regulation with, consequently, a low level of public services, while others, such as the Scandinavian countries, have taken the “high road” of social investment, meaning higher taxes and a larger public sector.

Messrs Keating and Harvey concluded that success for an independent Scotland was possible, but that hard choices would need to be taken. But as this column has noted innumerable times, the modern SNP isn’t much good at hard choices, preferring to fudge and triangulate lest they annoy current and (especially) potential Yes voters. Thus the 2014 independence White Paper tried to take both the low and high roads, quixotically mixing low taxes and social investment.

That model is yet to be significantly revised, although it seems unlikely the “Growth Commission” chaired by former SNP MSP Andrew Wilson, who’s very much on the right of the party, will opt whole-heartedly for the high road. And if he doesn’t, sticking to the same high growth/low tax model long advocated by the Salmondistas, it’ll inevitably annoy the low road-inclined elements of the Yes movement such as the Greens and Radical Independence crowd.

And even if that ideological dilemma was to be resolved, what of Scotland’s world role in terms of defence and foreign affairs? Removing Trident is obviously a red line, and were Scotland to become independent that would make a lot of sense – the so-called “independent” nuclear deterrent has long been little more than post-imperial willy waving on the part of the UK – but having long posed as defenders of Scotland’s armed forces against “Tory cuts”, the SNP would find it difficult to radically scale that back, even though there’s a strong argument to do so, a la Ireland under the Nato umbrella.

As the late Robin Cook discovered, meanwhile, there is no such thing as an “ethical” foreign policy; nations do not have friends or enemies, only interests, and as a newly independent small nation perhaps outside the EU, Scotland would have to pursue those interests with tremendous care. It might like the idea of “standing up” to Donald Trump, but in reality it’d have to seek a special relationship of its own. Uncomfortable compromises would be unavoidable.

And if all this was uncertain and complex a few years ago, it’s even more so in the years ahead. Now we have America First competing with Britain First and, perhaps by late next year, Scotland First (which, as it happens, was an old SNP slogan).

“Stop the world,” quipped Winnie Ewing nearly half a century ago, “Scotland wants to get on.” But if, in the context of a second referendum, the SNP wants to move beyond pithy quotes, they’ll need to do some hard thinking about an independent Scotland’s likely role in an increasingly turbulent world.