A blond youth on a small stage sings America the Beautiful with camp stylings for an audience whose neo-Nazi members give him enthusiastic Hitler salutes: the grotty little cabaret turn captured on video could have come straight from Cabaret, the musical about Berlin in the last days of the Weimar Republic. But this video was filmed last year, in Dallas, Texas, and the singer was an editor for Breitbart News, one of the most energetic supporters of Donald Trump’s campaign for the presidency.

The revelations reported this week sound like an air-raid siren to warn us that the institutions and the decencies on which our civilisation rest are under a determined attack. Steve Bannon, the leader of Breitbart, went on to become Mr Trump’s chief strategist in the White House before leaving earlier this year; while on the internet or at the ballot box the alliance between “respectable” authoritarian xenophobes and explicit white nationalist movements continues to make progress.

This alliance, the “alt-right”, forms a new identity politics of wounded narcissism. White boys of all ages, consumed with rage and self-pity, dream of themselves as heroic blond warriors for civilisation, but in real life they mostly just gang up to bully women. They seem the pallid mirror images of the lost souls who form one of the most common sorts of jihadi sympathisers in the west.

This makes the “alt-right” more powerful and more dangerous than previous far-right movements, since it uses the deceptive intimacy of online life to merge the political and the personal in a way that conventional democratic politicians find increasingly hard. One of the earliest manifestations was Gamergate, the campaign of bullying and abuse directed at female game developers three years ago. The relentless harassment, death and rape threats and deliberate violations of privacy were all parts of the larger fascist pattern.

As individuals, the members of the online mob enjoyed their own cruelties, their angers, and self-righteousness. Pleasuring themselves with these vices, they form a shadowy collective larger and more frightening than anything any individual could become. This is a great part of the attraction of the movement, but it is also why we must resist it with an equally firm collective resolve.