It was not an auspicious start to Ukip's official campaign in the Aberdeen Donside by-election to the Scottish parliament. A crowd of angry nationalists laid siege to Nigel Farage in an Edinburgh pub and he had to be escorted to a waiting police van for his own safety.
Looked at one way, there's no little scope for humour in such a confrontation, and indeed the Daily Mash captures the mood quite well. But beyond that - and it is worth reminding the DM writers that the non-Scottish Farage has never had his followers assault an opponent - the incident highlights both the challenges facing Ukip and, as seriously, the SNP and the Scottish 'Yes' campaign, both topics which I've written about in IBTimes UK and ConservativeHome in recent weeks.
For all of Farage's creditable unionism, the party is struggling to live up to the 'UK' part of its name. With no presence in the devolved assemblies (outside a lone defector in the Northern Ireland Assembly) and a party programme built around nostalgic south-of-England Toryism it is hard to see how it will be able to appeal to a broader range of voters than those who formed the core of Tory support during the post-1997 wilderness years.
Yet the mob doesn't just pose a challenge to Farage and Ukip. For the Yes campaign, the problem is how to make sure the behaviour of groups like Radical Independence and other hardline nationalist outfits doesn't come to stain the wider Scottish nationalist movement.
For whatever historical reason, Scottish nationalism has managed to acquire a degree of social acceptability that has eluded its English and British counterparts. In England, an angry nationalist mob attacking a "foreign" politician would almost certainly be condemned as far-right behaviour, even if the mob in question claimed to be resisting far-right politics of a different stripe (as the English Defence League did in its early days). Xenophobic political thuggery is wrong, even when the target is allegedly, potentially, xenophobic.
Direct action left
It is true that the attack on Farage is not quite a uniquely Scottish phenomenon. Since Ukip's "breakthrough" in the English local elections other "anti-fascist" groups, such as Hope Not Hate, have decided that Ukip fall within their remit (which in my view lends the word "fascist" a truly McCarthyite breadth), and elements of the "direct action" left have never had trouble distinguishing their politically-motivated and violent suppression of freedom of speech and assembly from the potentially similar actions of their "fascist" opponents.
But the less interested wider public is less prone to such hair-splitting. Nationalist mobs denouncing "English" politicians and attacking parties of the democratic right might break the illusion that Scottish nationalism is a different beast and scare off moderate, middle-class supporters.
Thus the SNP's declining to denounce Farage's treatment might prove unwise. Unpalatable as it might be in the short run to have any kind words for a man so utterly opposed to his separatist vision, in condemning the behaviour of Farage's harassers Salmond could look magnanimous and statesmanlike, as well as putting some clear blue water between the mainstream separatist campaign and extreme Scottish nationalism.