Corbynism is on the brink of an unlikely breakthrough in the USA

This Saturday in sunny Las Vegas, the Democrats put their money on red. Senator Bernie Sanders won the Nevada caucus with 47 per cent of the vote and is now the clear frontrunner for his party’s nomination.

This is remarkable, not only because he’s a self-proclaimed socialist, or a 78-year old who recently had a heart attack, but because he’s only been a Democrat since last year. His three wins in a row are as much a repudiation of the liberal establishment as a warning to Donald Trump.

It’s tempting to write him off as the American Jeremy Corbyn and, yes, there are similarities. Bernie’s signature policies are a massive expansion of free healthcare and a green new deal, and he’s a trenchant critic of US foreign policy. He actually spent his honeymoon in the Soviet Union. Trump’s attack tweets practically write themselves.

They might not work. A narrow majority of US voters don’t like socialism but the young are warming to it and a significant prorpotion say they don’t even know what it is. As in Britain, the general idea might be unpopular but the specifics go down well. The cooks union in Nevada opposed Bernie because his heathcare-for-all programme threatened their own private insurance plan, yet their members ignored the leadership’s advice and voted for him anyway.