Discussion of currency wars has broken out again in the run-up to this week’s G20 finance ministers' meeting in Moscow. This column points to the underlying policy choices responsible for the recurring currency disputes and the feeble ex-post rationalisations for them.

Switzerland has pegged its currency to the euro at a level that helps it sustain a 12% current-account surplus and one of the lowest unemployment rates in Europe. This column argues that the Swiss peg involves currency manipulation that is, as far as Europe is concerned, the same order of magnitude as China’s intervention. It has had a significant impact on the euro exchange rate and a non-negligible effect on the EZ economy.