President Donald Trump’s tweeted demands for a weaker dollar, and his subsequent designation of China as a “currency manipulator”, have sparked fears that his trade battles are morphing into a currency war. The last time we had a global competitive devaluation was in the 1930s, as the world descended into the Depression. But today, currency values are set in huge global markets rather than against gold. That leaves the US alone on the battlefield, armed with only the equivalent of a pea shooter.

The US will not succeed in unilaterally weakening the dollar and could spark a global recession, raise political tensions and upend financial markets in trying. Read about it in my latest column in the Financial Times.