When Hitler swallowed Czechoslovakia in 1938 and then divided Poland with Stalin in 1939, my parents’ generation decided, coming home from the war, to place the sovereignty of nation states at the heart of the United Nations Charter. With the operation in Venezuela, our generation has to ask, and not for the first time, whether anything now survives of a legal doctrine designed to protect the weak from the strong. Let’s not make the mistake of believing that it was United States president Donald Trump who dealt sovereignty its coup de grâce. We are not in a new and shocking narrative but...