The French centre’s troubles are hardly unique. Populist-right parties are surging in many democracies. Yet in Hungary, the Netherlands, Poland, Romania and elsewhere, centrists have found ways to beat them. Besides a willingness to sound firm on immigration and crime, politicians who vanquish populists tend to share three traits.

After the Trump administration blocked a new ambassador to Washington, the country expressed regret for a post from a French official social media account.