“If there is going to be class warfare in this country, it’s about time the working class won that war.”

Those were Bernie Sanders’s words on the campaign trail last August as he set out to try to win the presidency. If you said in 2015 that this kind of politics would twice win millions of votes in a national election in America, no one would have believed you.

Before Bernie Sanders socialism in America was not just on the margins, it had been almost wiped out. The left-wing radicalism of the early twentieth century — from trade union militancy and the rise of the IWW to Eugene Debs’s campaigns, Woody Guthrie, Paul Robeson, and the Popular Front during the Second World War — was comprehensively routed from American life by Joseph McCarthy’s purges in the 1940s and ’50s. By the time the Civil Rights Movement came around, socialists like Bayard Rustin, and even Martin Luther King Jr himself, were forced to hide their colors.