“WE’RE supposed to have lost the referendum but look at us now!” yells Sandra White, a Scottish National Party (SNP) politician. Bagehot was already gazing in wonder. On a dreich weekday night, the community hall Ms White is addressing in Kelvin, central Glasgow, is packed with SNP members. Young and old, brown and white, they bubble with nationalist verve and eagerness to get door-knocking and leafleting. A show of hands suggests most have joined the party since that black day, September 18th, which was supposed to have laid the nationalist cause to rest “for a generation”, in the words of the party’s then leader, Alex Salmond. Back then—ten weeks ago—the SNP’s Kelvin branch had 310 members; now it has 1,734. Amazingly, this dramatic five-fold increase is being replicated across Scotland.

On referendum day, the SNP had 22,000 members; now it has 95,000. Almost 4,000 signed up on November 22nd during a televised rally for Mr Salmond’s successor, Nicola Sturgeon, which was attended by 12,000 people. The SNP is now Britain’s third biggest party, more than twice the size of the Liberal Democrats, the next biggest, whose thinning ranks are more typical of British parties. Next in its sights are the ruling Conservatives, whose membership, currently around 130,000, has fallen by half in less than a decade. What are its followers imbibing?

Hope for a better future, conviction that the nats can deliver it, and an aching for the sense of purpose and belonging that many found in the separatist campaign. This is what unites the SNP newbies in Kelvin. Many are recent defectors from other parties, such as Suzanne, a former member of the Labour Party, who rebranded her central Glasgow pub the “Yes Bar” during the referendum campaign and is now looking for an SNP ticket for next year’s general election. Or Tommy, a 21-year-old student and former Lib Dem supporter, who had not considered voting SNP before the “brilliant and invigorating” referendum campaign. “It was a real comedown when it ended,” he laments.

In a time of dying parties, a fracturing electorate and falling turnout—especially among younger British voters, who are about as likely to bungee jump off the Clifton suspension bridge as join the Tories—Scotland’s referendum turns out to have been democratic catnip. Scots have historically voted less in general elections than the British average; the percentage who say they will definitely vote next year is, at 60%, ten points above it—apparently due to surging support for the SNP. On current polling, this would give the separatists most of Scotland’s 59 seats—41 of which are held by Labour—and make it the third biggest party in Westminster. No wonder nobody talks of its struggle being mothballed these days. An SNP worthy in Kelvin made so bold as to suggest Mr Salmond’s pledge had in fact been honoured, a political generation having passed when Ms Sturgeon succeeded him.

A shoo-in for the Aberdeenshire—currently Lib Dem—seat of Gordon, the former SNP leader will lead the assault on Westminster. As one of Britain’s most charismatic and divisive politicians (“He’s Marmite,” Scots say, “You love him or hate him”), Mr Salmond has sworn to “rumble up” Westminster and secure “real power for Scotland”. That means he plans to be as obstructive as it takes on any non-Scottish issue to wield maximum influence on Scottish ones. Given the existing difficulty of passing legislation—because of the failure, which is likely to endure, of either the Tories or Labour to command a majority—this is a dire prospect for a system whose frailties Mr Salmond has a record of turning to his advantage. His campaign was fuelled as much by anti-Westminster as by nationalist sentiment; this is another reason to suggest the SNP means to play the wrecker.

Yet it also shows why the allure of nationalism, which British, especially Labour, politicians have serially underestimated, is an inadequate explanation for the party’s rise. The fundamental difference between the Yes and No campaigns was that the former offered a positive and dynamic vision of Scotland’s future, while the latter, after much head scratching, promised more of a dreary status quo. This was not all the unionists’ fault. The separatist promise of, to quote Suzanne of the Yes Bar, “fairness, a better society, no more cuts, no more poverty”, was fanciful. The No campaign, whose more realistic prognostications were inevitably dull by comparison, was also rendered more negative, monochrome and risk-averse than it would otherwise have been by its cross-party design. But, those caveats admitted, the failure of mainstream British politicians to offer a compelling vision to set against the populists’ is also fundamental and, as long as they cannot rectify this, it condemns them to further decline.

Boney, blotchy and covered in hair

It would help if they would stop running down Britain’s present. This is partly a consequence of their convergence in the centre, which makes it hard for voters to distinguish between them, even as they continue to knock lumps out of each other’s records. The result is an exaggeratedly gloomy view of a country whose staid future largely reflects the fact that it is already pretty rich and successful. A more optimistic take on Britain’s present would be a useful counter to the Utopians—yet insufficient. Mainstream politicians need a compelling vision of their own.

In the fag-end of the current parliament, and the round of austerity that has defined it, there are signs of them working on this. The tax cuts promised by George Osborne, the Tory chancellor, may be unaffordable; but at least they provide the beginnings of a rationale for the smaller state he wants. By contrast, Ed Miliband, the Labour leader, sees a bigger, probably also unaffordable, state as the answer to most of the deficiencies he claims to encounter daily. These are starting points. But for anxious voters in Scotland and elsewhere, semi-beguiled by populist fantasies, such half-ventured notions are not visions. They are the gapings of spilt goldfish, gasping for air.