It is staggering how markets and almost everyone this columnist engaged with in recent months were utterly convinced Donald Trump was bluffing on tariffs. He was just negotiating. It was the art of the deal.

Even immediately before the April 2 announcement, US stocks went on a bizarre rally based on some investors’ belief that they had the inside word on the outcome. They must have somehow got wind of a reference to the 10 per cent minimum tariff and thought that was the end-game.