So Americans should be thankful they have one of the last functioning nation-states. Europeans, because they've been so inept at exercising it, no longer believe in national sovereignty, whereas it would never occur to Americans not to. This profoundly different attitude to the nation-state underpins, in turn, Euro-American attitudes to transnational institutions such as the United Nations. But on this Thanksgiving the rest of the world ought to give thanks to American national sovereignty, too. When something terrible and destructive happens – a tsunami hits Indonesia, an earthquake devastates Pakistan – the United States can project itself anywhere on the...