Bernie Sanders and Jeremy Corbyn are both down – but that doesn’t mean the movements they started are out

The question is whether the younger enthusiasts for these ideas will keep the faith as they grow older, writes Mary Dejevsky

It’s a big positive for the left that a candidate like Sanders can challenge so convincingly for the presidency – even if he loses to Biden (AP)

Joe Biden, the former US vice president, pulled off the seemingly impossible this week, when he caught up and overtook Bernie Sanders in the race for the Democrat presidential nomination. Biden’s prospects had been practically written off after swingeing victories by Sanders in the early caucuses and primaries.

Now Biden is back with a vengeance and, while the contest still has weeks to run, his momentum looks hard to reverse. He went into Super Tuesday with the endorsement of the early favourite, Pete Buttigieg, and goes into the next votes on 10 March with Michael Bloomberg, the latest and potentially most valuable dropout, signed up too.

Biden’s comeback suggests three things about the state of US politics in the spring of this election year. The Democrats remain as divided as they were four years ago between the radical left (in US political terms) and the centre, but when presented with a direct choice between left and centre – without any of the shades in between – a majority of primary voters seems to prefer to play safe.