WHEN Alex Salmond suddenly announced his resignation, we could not be certain that Nicola Sturgeon, although she was his obvious successor, would be able to make the case for independence as effectivelyas he had.

After eight years, in which the SNP has been the most popular party in three UK General Elections, two Scottish parliamentary and local government, elections, and a European Parliament election, Ms Sturgeon’s effectiveness as a campaigner is beyond doubt.

Perhaps history will treat her as a transitional figure who provided leadership between the first, unsuccessful Scottish referendum of 2014, and a subsequent, successful one, in which the people of Scotland confirmed their sovereignty.

Still only 52, it may also be that her most substantial work lies ahead of her, rather than behind her.

With independence the focus of Scottish political debate over the last decade, it is perhaps easy for us to forget that European countries do not typically split asunder. They might trade territories or dissolve after wars or civil conflict.

In the 400 years of the modern nation state, Norway is the only one to have achieved independence through the ballot box. Before achieving independence, it was part of Sweden for less than a century, handed over from Denmark at the Congress of Vienna in 1815 as a form of compensation for Russia’s acquisition of Finland.

The famous “velvet divorce” between Czechia and Slovakia was ratified in a backroom deal reached between politicians who simply did not want to work with each other.

Had the measure been put to a popular vote, it might well not have happened – the dissolution vote in the old Czechoslovak Parliament had to be held three times. It was an appropriately chaotic end to the country.

Throughout her time as First Minister, Nicola Sturgeon was never able to find a way of carrying out that decisive second test of Scottish public opinion. The Norwegian route was never available.

Nor could she find a partner for negotiations in the mould of the brashly conservative Vaclav Klaus, the Czech free-market economist, prime minister and eventually president, who was more than willing to allow Slovak independence.

When people criticise Nicola Sturgeon for failing to bring matters to a head, they propose alternatives, in which somehow “the international community” will recognise Scottish independence.

Perhaps this will be the route which Scotland takes. But they need to realise it is a largely untried route and that it too might well fail.

Repeatedly, political experts have praised Nicola Sturgeon as a great political communicator. Compare her with the prime ministers she has worked with: David Cameron, languidly campaigning against Brexit; Theresa May, robotically seeking to batter through opposition in her own party; Boris Johnson, with his shuddering spasms of incoherent speech; Liz Truss pausing despairingly before mechanically reciting the line to take; and even Rishi Sunak, whose earnest desire to please makes him a great Tony Blair impersonator.

Nicola Sturgeon’s communications skills helped to maintain support for the idea of independence. Had different political opportunities been available, perhaps she would have used those skills to build a clear consensus for independence before a referendum took place. Perhaps, freed from the burdens of office, she will do exactly that.

IT seems unlikely. I suggest that plausibility in economic matters is essential to success in political communications at a wider level, so that Nicola Sturgeon may well have been able to operate within her comfort zone as First Minister.

The devolution settlement means the Scottish Government concerns itself mostly with the funding of services.

True, there is some freedom at the edges for it to raise some extra revenue, but the complex arrangements of Barnett consequentials and block grant adjustments mean that public finance experts become animated about how policy measures might increase total spending a fraction of 1%.

The small differences between income tax bands in Scotland and the rest of the UK demonstrate a desire to address inequality. Their size means that they are largely symbolic.

Adam Smith’s political economy was ultimately a study of the management of resources within states. Without political economy – without understanding resource management – states drift.

Great empires subside into insignificance, as the global distribution of economic capabilities shifts between countries.

Relative to the rest of the world, the UK has been losing ground for much of the last 150 years. Looking inwards, rather than outwards to face the world, England voted for Brexit. The extent of “buyers’ regret” has not yet fully affected UK politics. In Scotland, it poses, but also clarifies, the problem: is it better to be part of the UK, or part of the European project?

Economists like to see the larger markets, which come about with greater integration of economic activity across nations. If we look across the Irish Sea, turning from Britain to Europe was important for its economic success.

Around the Baltic Sea, and in much of Central Europe, there are many states which have cheerfully embraced the European project and which are reaping the benefits of greater prosperity.

Leading Scotland to independence should not mark the end of a career. While age brings age and experience, it also brings an attachment to ideas and ways of thinking which is hard to break.

Achieving independence would no doubt be exhilarating for the SNP’s new political leader. Making it work will be enormously complex, and require the fearlessness of youth.