LONDON — In Westminster these days, there is only one topic that matters: the EU referendum. Rumors and counter-rumors swirl around the final shape of David Cameron’s renegotiation, the likely reaction of ministers wavering between In and Out, and what it will all mean for the eventual vote.

It can be easy to forget that there are many other votes this year. Britons go to the polls May 5 to elect their devolved representatives in Northern Ireland, Wales, Scotland and London, as well as a mayor of London, local police and crime commissioners (in England and Wales) and sundry councilors across England.

Of these various races, the London mayoral contest has captured what little of Westminster’s attention can be diverted from European affairs. Not only does it pit the Muslim son of a bus driver (Sadiq Khan of Labour) against the environmentalist son of a right-wing billionaire (Zac Goldsmith of the Tories), but it is seen as the first big test of Jeremy Corbyn’s electoral appeal.

The Scottish race has received less attention, precisely because it is so predictable: Nicola Sturgeon and the Scottish National Party are set to win another comfortable majority. Yet what it lacks in drama, it makes up for in significance.

The SNP argues that Tories are evil, England is run by Tories, and therefore Scotland must leave England.

As with Margaret Thatcher and Tony Blair in their heyday (though she would not appreciate either comparison), Sturgeon’s ascendancy is the settled fact of Scottish politics. Even commentators viscerally hostile to the SNP, like Chris Deerin and Alex Massie, are forced to accept the hegemony of “Queen Nicola.”

The fact that the SNP’s dominance is so complete, however, can blind us to how remarkable it is. The government in Edinburgh was set up using a proportional representation system designed, in large part, to keep the Nationalists (aka the “Nats”) out. With Labour strong, the Liberal Democrats credible and the Tories still clinging on to a few seats, it would be impossible for the SNP to win an absolute majority.

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The man who changed that was Alex Salmond, Sturgeon’s predecessor. First, in 2007, he won enough seats to form a minority government. Then he turned that track record into a solid majority — a remarkable feat. It was enough to persuade David Cameron to agree to a referendum on independence, for fear of Salmond launching his own (theoretically non-binding) plebiscite.

Yet still there lingered a suspicion — if only in London — that the SNP was a cult of personality more than a party of government. Its enemies comforted themselves by recalling how, after Salmond stepped down for the first time in 1999, the party had rapidly succumbed to its own internal contradictions.

That this did not happen after the independence referendum, and Salmond’s subsequent departure from office, owes much to the sense of grievance that united the 45 percent who had voted in favor — and something to Cameron’s provocative attempt to yoke the promised devolution settlement to the assuaging of English grievances, too.

But it also owes an awful lot to Sturgeon. She has proved herself the Stalin to Salmond’s Lenin, turning a revolution into a regime. At the Westminster elections in May, the SNP swept the board, turning vast Labour and Lib Dem majorities into near-impregnable majorities of its own.

Even then, there was talk during Labour’s leadership election that Jeremy Corbyn’s left-wing politics would strike a chord with Scottish voters, especially those who had condemned the party as “Red Tories” after its Faustian alliance with Cameron during the independence referendum. So far, there is absolutely no sign of this happening.

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Which leaves us in a curious situation, in which English and Scottish politics are funhouse mirrors of each other. Both have not just a natural party of government — the Tories in London, the SNP in Edinburgh — but a party that is utterly dominant. In neither place does that make for good government.

But the bigger concern is that both of these parties define themselves, in essence, against the other. The SNP argues that Tories are evil, England is run by Tories, and therefore Scotland must leave England. The Tories argue that the SNP are dangerous separatists, they cannot be allowed a share of government in London, and the only way to prevent that from happening is to vote Tory.

The Tories may be anti-SNP, but they are not anti-Scottish: They will do whatever they can to keep the Union together.

The next obvious flashpoint is the Brexit referendum. Scotland will, polls so far all suggest, vote to stay in. If England votes to leave, and carries the day, most experts predict a rapid end to the Union. The only dissenting voices come from anti-EU campaigners, who appear to specialize, as Chris Deerin pointed out recently, in clod-hoppingly patronizing explanations to the Scots as to what they are really thinking.

But even if that crisis is averted, the structural tension will remain. The center-left is entrenched in Scotland, the center-right in England. The Tories may be anti-SNP, but they are not anti-Scottish: They will do whatever they can to keep the Union together. But the SNP will have no compunction about doing whatever it can to pick the Union apart, or simply to channel Scottish politics along a different course.

When, on May 5, the cameras cut to a beaming Nicola Sturgeon, celebrating another thumping victory in the Scottish elections, she will be smiling for a very good reason: Because she knows that time is on her side.

Robert Colvile is a regular contributor at POLITICO.