As visual metaphors go, it wasn’t bad: Donald Trump ignoring expert advice and risking calamity by staring up at the sun as the moon’s shadow passed across America. Self-destructiveness has become a habit for this president — and for his advisers. A recent example: former White House chief strategist Steve Bannon called Robert Kuttner, a prominent progressive journalist, to declare that his internal foes in the administration were “wetting themselves”. Shortly after Mr Kuttner wrote about the conversation, Mr Bannon was out.

But the truly harmful temptation here is not eclipse-gazing or indiscreet interviews. It’s another idea that Mr Bannon proposed to Mr Kuttner: that the US was in “an economic war with China”. It seems intuitive; many ordinary Americans feel that they cannot win unless China loses. But the world economy is not like a game of football. Everyone can win, at least in principle. Or everyone can lose. Falling for Mr Bannon’s idea of economic war makes the grimmer outcome far more likely.

Like many dangerous ideas there is some truth in it. The American middle class has been suffering while China has been booming. Branko Milanovic, author of Global Inequality, has produced a striking elephant-shaped graph showing how, since the late 1980s, the rich have been doing well, as have many other groups, including the Asian middle class. But earnings near though not at the top of the global income ladder have stagnated. That does not demonstrate harm from China: there is the fall of the Soviet Union to consider, and the struggles of Japan.