Therefore we should be paying more attention to the race for the Democratic nomination. Way out in front is a leading group of three candidates: Joe Biden, Elizabeth Warren and Bernie Sanders. But, not to put too fine a point on it, they’re old. Sanders is 78, Biden 76 and Warren 70. While Warren is on top of her game, Sanders and Biden have put in some rather rambling performances in the TV debates so far.

If any of these three withdraw from the contest, they’d leave a big gap. That’s especially true of Biden – the standard-bearer of the Obama-Clinton wing of the Party. Which is why the rest of the candidates still matter. Without Biden, a younger moderate would be catapulted into the front ranks and quite possibly the White House. But who?

Of the establishment favourites, Kamala Harris is fading, Mayor Pete Buttigieg has lost momentum and Beto O’Rourke has got nowhere apart from the front cover of Vanity Fair.

But keep an eye on Andrew Yang – a recent poll shows him coming from nowhere into fourth place, behind the three front-runners.

Yang is a 44 year old entrepreneur and philanthropist. He’s very much a centrist, but with eye-catching policies – not least his championing of Universal Basic Income. His proposal is that every adult American would get a monthly citizen’s income of $1,000. Lest that sound too socialist to American ears, he’s called it his “Freedom Dividend”.

A clever name, but it’s not really about freedom but security against the forces of economic disruption (especially automation). Where Donald Trump rose to power on promises of building a wall along the Mexican border, Yang is taking his offer of protection straight to voters’ bank accounts.

Personally, I think it’s the wrong solution to the wrong problem (the robot economy is a long way off). But, as a political message, it works.

Trump’s wall is mostly gaps. His trade war against China has got bogged down. The voters that made him President are looking for new solutions.