It’s difficult to remember the last time an advanced economy embarked on a course of self-destructive behaviour of the magnitude seen by the United States since Donald Trump returned to the White House. Brexit – an emblematic act of economic self-sabotage – pales in comparison.

The new protectionists describe tariffs as a way to ensure a manufacturing revival, or as a negotiating tool. By far the most honest description of the economics of a tariff, though, is a special tax on the most efficient source of supply for businesses and consumers. Put like that, the idea of “retaliation” seems much less obvious than it does to politicians who want to impress voters with the image of strength against foreigners.