‘How do you feel when you go back to Gary?’ I ask Joe Stiglitz. ‘Well, frankly, I get depressed,’ he replies. ‘The American middle class was created in places like my home town and is now struggling badly — which makes me sad.’

Stiglitz, a Nobel prize-winning economist and the closest thing the left has to an intellectual superstar, grew up in Gary, Indiana, during the 1950s, when it was the heart of the booming US steel industry.