That's one separatism crisis down, one to go. Now that the electoral demolition of the Parti Québécois has postponed the possibility of a Quebec independence referendum by at least half a decade, we ought to turn our attention to the far more real sovereignty vote to be held in Scotland in September – in good part because it tells us a lot about where the PQ got lost, and about what has happened to nationalism in the 21st century.

What stands out, in both independence movements, is the prominence of Sikh turbans and Muslim head coverings. In Quebec, they appeared on proposed signs detailing unacceptable garb for public employees under the PQ's secular charter, and those who wore them became targets. In Scotland, they appear on the heads of supporters of the separatist Scottish National Party, and those who wear them have become key members of the SNP's voting base.

That's the big difference: While Quebec nationalism collapsed into notions of "Québécois" identity and the PQ fell to portraying immigrants and religious minorities as outside influences to be "accommodated," Scottish nationalism has gone in the opposite direction, purging itself of any trace of "Scotland for the Scots" ethnic nationalism.

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I recently spoke with Osama Saeed, the Scotsman who runs Al-Jazeera's media department and who ran for Britain's Parliament as an SNP candidate in 2010. He told me that he never had any sense that his Muslim faith or Arabic ancestry put his Scottishness in question or made him unwelcome in the movement. SNP parliamentarians and candidates with names like Tasmina Sheikh and Humza Yousaf (the party's external affairs minister) are held aloft by the party as model separatists; this isn't tokenism but a shift to an entirely different sort of nationalism, one based on a territorial claim of economic sovereignty rather than a racial or linguistic bid for self-determination.

Quebec's sovereignty supporters have long been divided between ethnic-nationalist and civic-nationalist factions, and the PQ has played an ambiguous role, at times promoting itself as a multiethnic social-democratic movement and at others – such as under Jacques Parizeau, Bernard Landry and Pauline Marois – as a movement for the self-determination of the Québécois people, defined in ethnic and linguistic terms.

Behind many old-school separatist movements lies the late-19th-century concept of ethnic self-determination, which was given half-hearted official recognition in the Versailles Treaty and went on to create considerable bloodshed in the 20th century as former empires and federal countries collapsed into ethnic territorial claims. The uni-ethnic state was never more than an artifice of the imagination, and its legacy is so sad and unsuccessful that few voters are likely to back the creation of a new one. Ms. Marois learned this too late: The majority of potential separatism supporters, it turned out, were interested in economic and political self-sufficiency, but not ethnic solidarity.

Scotland's separatists figured this out a generation earlier. "The SNP was never happy with ethnic-nationalist types within its ranks. It marginalized them at every opportunity," says Peter Lynch, the author of a history of the SNP and a lecturer in politics at the University of Stirling.

In the early 1990s, SNP leader Alex Salmond led the most recent major purge of SNP ethnic nationalists. The party banned the right-wing Siol nan Gaidheal ("seed of the gaels") movement and expelled party members who had joined the radical Settler Watch and Scottish Watch movements. The SNP's most famous slogan, "It's Scotland's Oil," and its centre-left message of higher social spending financed by petroleum windfall held a lot more appeal than Braveheart-flavoured jingoism. Besides, the Scottish people had become increasingly multihued and multireligious.

"As a party, it wanted to be taken seriously," Mr. Lynch says, "and that meant policies and electoral contests rather than any ethnic appeal that would be divisive internally within Scotland and make the party look like racists … there was no constituency in the party for ethnic stuff."

Strictly ethnic separatist movements still exist in some places – consider the Flemish Vlaams Belang party in Belgium or the Basque ETA in Spain – and Vladimir Putin has gone to great lengths to stir up ethnic-Russian disgruntlement in the Eastern European perimeter. These movements tend to be extreme and popular only among the extremely disenfranchised. Having a nation-state of your own does not hold the appeal it once did: The ethnic breakaway country has a very poor track record.

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As a result, as we see in Scotland, "money and the ethnic vote" have gone from being separatists' declared enemies to their new rallying cry.

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