It takes quite a lot to make you feel sorry for the Swiss, but Donald Trump has managed it, imposing 39 per cent tariffs on its exports for a reason no one can entirely fathom. He’s also turned his import tax scattergun on Brazil and India, but his most extraordinary recent act is the ad hoc 15 per cent quasi-export tax on chipmakers Nvidia and AMD’s sales of semiconductors to China.

The wrongly-named “reciprocal” tariffs Trump announced on April’s so-called “liberation day” were always risible, but the deficit-based formula that generated them was at least vaguely related to their stated aim of reducing trade imbalances. The transmutation of those tariffs and others into a Christmas tree on which different parts of the administration and Trump himself have hung their geopolitical and commercial whims has demolished any sense of coherence.

The Brazil tariffs were imposed to support former president and fellow conservative election-truther Jair Bolsonaro, while India’s punishment supposedly reflected its purchases of Russian oil, despite Trump’s apparent closeness to Vladimir Putin. The chip export levy makes no sense on a number of levels. If Trump is trying to deprive China of advanced technology, a 15 per cent charge won’t remotely do it; if he wants to raise revenue then by definition it will only work if it doesn’t deter Chinese buyers; and by his own logic, hampering exports will increase, not reduce, trade deficits.