Moments of turmoil and uncertainty favour the brave. Is the SNP brave enough to call a second independence referendum after last night’s EU referendum result or is that foolhardy – and even undemocratic? And maybe as important: who will decide?

The core argument is already familiar to most interested voters, because pollsters flagged up the possibility of another Scottish referendum after a leave vote throughout the campaign. Now that doomsday scenario has come to pass.

Scots voted to remain in the EU by a 24- point margin. Every council area voted to stay. The map is as yellow north of the border as it is blue beneath it. Such “regional” variation would hardly have been worthy of comment in times past. But the 2014 referendum changed all that. The no side argued vigorously that an independent Scotland would not be automatically accepted as a new member of the European Union, backed by the European commission president, José Manuel Barroso, who said membership would be “extremely difficult, if not impossible”.

Yes campaigners argued that there was simply no precedent for the expulsion of 5 million EU citizens against their will, and the credibility of naysayers such as Barroso were soon questioned. But that uncertainty sat upon other uncertainties, such as the shared use of sterling, to create a climate of nervousness and an expectation of instability in a post-yes scenario. By contrast the no campaign led by the UK government offered cast-iron certainty on both issues. Economic stability and a place in Europe could only be guaranteed by a no vote. For many wobbly voters that was the end of any dalliance with independence.

Now it’s evident to all that Scots voters were sold not one but two pups. Britain now faces economic turmoil and Brexit. And Scots find themselves facing constitutional deadlock yet again. Clearly it’s a situation Nicola Sturgeon intends to exploit – carefully.

The Scottish first minister told a press conference in Edinburgh that the prospect of a second referendum on independence is back on the table, but before that her first priority is to find some way to keep Scotland in Europe. Small nations such as Greenland and the Faroes were allowed to opt out of Denmark’s EU membership – and while that’s obviously different from a small nation trying to remain in while the “mothership” departs, it might not be impossibly different.

Constitutional lawyers suggest Scotland’s best chance for a Brexit optout is to make that argument while Britain makes arrangements to leave. David Cameron has said he will let the new Conservative leader and prime minister trigger the article 50 process – and his successor must be found within the next three months. So Sturgeon’s window for a successful EU intervention is short, and since the outcome of this summer’s horse-trading could dramatically change the way Scots view the desirability of continued UK membership, the Scottish government must prepare legislation now to let a second independence referendum take place if the need arises.

Will the UK government allow that? In the circumstances it would be patently undemocratic for them to refuse. Will the SNP win it? That’s still the $64,000 question.

Scotland had a slightly lower EU referendum turnout than the rest of the UK – we’ve had three major elections/referendums in as many years, with local elections due next year, and voter fatigue may have set in. Alternatively though, that lower turnout could be an indication that EU membership is not the huge issue for Scots that it’s become for voters south of the border. Equally, 55% of Scots voted to stay inside the UK less than two years ago and, while the “once in a lifetime” pledge was not contained in a manifesto or made by the present SNP leader, Sturgeon knows she will rile as many Scots as she pleases with a premature referendum.

On the other hand, a time of political and economic turmoil may offer the starkest possible contrast between a free-market-oriented, immigration-obsessed, rightwing, splendidly isolated England and a “modern, open, inclusive and pro-EU” Scotland, as the SNP leader characterised her fiefdom on Friday.

Just as many Brexit voters decided the UK has become the odd one out among European club members, hesitating over integration as the rest push on, Scots might decide Britain’s overall direction of travel doesn’t coincide with the roughly social democratic shape they’ve carved out.

It’s a tricky decision, but it seems Sturgeon has effectively taken it. If she pulls off the negotiating feat of the decade by keeping Scotland in Europe, confidence in her powers and in Scotland’s different trade, economic and foreign policies will rise. Since those powers are reserved to Westminster it won’t take long before the “fit” becomes intolerably bad.

On the other hand, if she fails and the Scots are hauled out of the EU, voters here must watch as former European powers revert to a UK government led by Prime Minister Johnson, Deputy Gove and Lord Farage. Maybe some – environment, fisheries and farming – will eventually find their way back to the Scottish government. But few will be holding their breath about the full quota of EU cash coming with any devolved powers.

The short-term looks messy for the UK, and as that mess develops, Sturgeon may decide she has the best chance to achieve a yes vote in a second referendum. On the other hand, as a politically youthful 45-year-old, she may consider discretion the better part of valour.

It’s clear now that the next three months will be critical for not one but two political clubs: the EU and the UK.