Jacob Mchangama’s new book, Free Speech, is touted (by the late great P.J. O’Rourke no less) as “the best history of free speech ever written”. It would be churlish to disagree, even if that praise sounds like one of those playground legalisms: “The best runner here wearing green socks and with a middle name Pete.” Even if it is the best history of free speech – which it probably is – it’s not entirely clear where that gets us.