The prime minister wants Britain to be “the most passionate, most consistent, most convincing advocate for free trade”. Under either Donald Trump or Hillary Clinton, and with world trade stagnating, it looks as if the job is increasingly likely to be vacant in March 2019, so Britain has both a vital duty and a golden opportunity. It worked for us before.
Next year sees the 200th anniversary of David Ricardo’s insight of “comparative advantage” — the counterintuitive idea that trade benefits “uncompetitive” countries as much as efficient ones.
If one country is better at making both cloth and wine than another, it can still pay it to get its wine, for example, by making extra cloth to swap for the other’s wine. Or, as somebody once put it, even if Winston Churchill is a very good bricklayer (he was) it still makes sense for him to write books or run governments, and pay somebody else to build his walls.