For students of constitutions, the important point is one which Colley makes in one of the many insights in this impressive book. Written constitutions follow a very similar pattern. Many of them could be the constitution of just about any country. What differentiates them is not their terms but the way that they are operated. They depend on a shared political culture which is peculiarly national, a culture in which politicians of radically opposed views are united in their desire to make the constitution work. The world is full of countries whose constitutions are filled with laudable provisions but have been subverted entirely legally by determined authoritarian governments which did not care to make them work. Putin’s Russia and Trump’s America have that much in common.