We hardly needed WikiLeaks to tell us, among many other things, that Nicolas Sarkozy, the president of France, is a vulgar man with authoritarian inclinations, or that Silvio Berlusconi, the Italian prime minister, is interested in sex. It isn’t even particularly reassuring to have our judgments confirmed for us by American diplomatic messages, for if they had said anything different we shouldn’t have believed them in any case. After the first slight frisson of pleasure at the discomfiture of powerful people and those in authority has worn off, a pleasure akin to that of seeing a pompously dignified man slip...