AP Photo

Europeans bemoaning the loss of their prominent world-governing (or, at least, photo-op-ing) role in the almost defunct G7 of industrial powers often worry that in future the world will not be steered by the broad and representative G20, but by a “G2” consisting of America and China. If so, the current war of words between those two giants should make the Europeans (and Japanese) feel lucky to be out of it. Harder to work out, though, is quite what this word-war means.