Three weeks to go before the referendum and Alex Salmond’s campaign for an independent Scotland has still to answer the simple question: Why cannot Scots remain at once proudly Scottish and contentedly British? What is it about the 21st-century world of pervious borders and multiple and merging identities that demands a nation of five million citizens should narrow its gaze and wrench itself from its neighbour?

A couple of decades or so ago, the Scottish National Party (SNP) would have had a ready answer: Separation meant escape from the yoke of English oppression. Had not Margaret Thatcher’s poll tax proved that Scotland was a vassal nation, a place where English Conservatives experimented with their nasty right-wing ideologies? Independence, in the eyes of old-fashioned nationalists, was synonymous with emancipation.

Salmond has by and large eschewed the cruder strains of identity politics, probably because he knows the SNP cannot gather a majority by banging a Jacobite drum of grievance. The union has not seen Scotland surrender patriotism or nationhood to the British multinational state. It has its own church, legal and education systems, a culture too vibrant to succumb to English subversion and, since 1999, a parliament in Holyrood. The union, you could say, seems to work.

The Scots, Salmond knows, are too canny to let old resentments rule their future. In successive elections, they have sent Nationalists to Holyrood and unionists to represent them in London. The SNP leader likes to quip that there are more giant pandas in Scotland than Tory MPs. Yet, at the 2010 election for Westminster, the Conservatives’ 17 per cent share of the popular vote in Scotland was just 3 points adrift of the SNP’s 20 per cent.

So Salmond preaches the gospel of inclusive nationalism. A Scotland set free would remain England’s best friend. This vision of a resentful marriage making way for the warm embrace of neighbours casts doubt as to why he wants separation at all. The Queen would remain Scotland’s head of state. The BBC may be rebadged as the Scottish Broadcasting Corporation, but would still broadcast popular British series such as EastEnders and Doctor Who.

The SNP plan for a lopsided currency union with the rest of the UK would leave economic power in London. A frontier without border posts would not allow any change in immigration policy. So why, the simple question nags, discard Scotland’s Britishness?

Salmond was widely judged to have won last week’s televised debate with Alistair Darling, the former Labour chancellor who heads the pro-union Better Together campaign. His pugnacious performance was said to cancel out Darling’s assumed victory in the first head-to-head encounter. What struck was the absence of any explanation of what Scotland gains from leaving Britain.

The first minister had a stab at it when he said that separation would remove the risk that a Tory government at Westminster might dismantle Scotland’s National Health Service. The snag is the Scottish health service is run by the Holyrood parliament. If Scotland wants to spend more on health it can do so under the terms of the existing devolution settlement; and after a promised further transfer of fiscal powers promised by the unionist parties, there would be no limit.

The idea that a Scotland more intuitively social democratic than England is on a different political trajectory is probably the best case that Salmond can muster, even if the divergence is often exaggerated. Yet, on its own terms, the SNP has yet to explain why Scotland cannot make its own tax and welfare choices within the union.

Salmond says that Scotland could be like, well, Norway. As everyone knows, Norway has oil, a high standard of living and strong social protections. An independent Scotland would also have oil. Ergo, it could be Norway.

Well, not quite. Norway has been saving its oil revenues for 40 years. Britain’s have been largely spent. And oil output is now falling. There is another catch. The SNP says Scotland would be an active member of the European Union. Norway shuns European integration. So, no, a separated Scotland would not be like Norway. Come to think of it, how many Scots, nationalist or unionist, want to swap Britishness for Norwegian-ness?

Though he cannot admit it, Salmond is left with the romantic pull of Braveheart nationalism. His campaign should not be underestimated for that. He is an accomplished communicator with charm to temper ruthlessness. The insecurities that flow from globalisation have stirred embers of ethnic nationalism across much of Europe. Like the English nationalist Nigel Farage, who runs the United Kingdom Independence party, Salmond has cast himself as an anti-establishment figure leading a popular uprising against the old elites. And he is much smarter than Farage.

That missing answer, though, also matters. The abiding characteristics of the modern world are a diffusion of power and the corrosion of the old rules-based international system. If like-minded nations are to prosper in security they will have to pull more closely together. Salmond’s argument for taking Scotland out of Britain is as flawed as Farage’s demand for Britain to leave Europe.

Salmond’s expansive nationalism scarcely conceals the cruder identity politics. He is asking Scots to turn in on themselves on September 18. The hope must be that, secure in their Scottishness and comfortable in their Britishness, most will reply: “What’s the point?”

— Financial Times