Nonetheless, the difficulty of forging a common identity in sharply divided democracies should not be underestimated. Most contemporary liberal societies were built on top of historical nations whose understandings of national identity had been forged through illiberal methods. France, Germany, Japan, and South Korea were all nations before they became liberal democracies; the United States, as many have noted, was a state before it became a nation. The process of defining the American nation in liberal political terms has been long, arduous, and periodically violent, and even today that process is being challenged by people on both the left and the right with sharply competing narratives about the country’s origins.

Liberalism would be in trouble if people saw it as nothing more than a mechanism for peacefully managing diversity, without a broader sense of national purpose. People who have experienced violence, war, and dictatorship generally long to live in a liberal society, as Europeans did in the period after 1945. But as people get used to a peaceful life under a liberal regime, they tend to take that peace and order for granted and start longing for a politics that will direct them to higher ends. In 1914, Europe had been largely free of devastating conflict for nearly a century, and masses of people were happy to march off to war despite the enormous material progress that had occurred in the interim.

The world has perhaps arrived at a similar point in human history: it has been free from large-scale interstate war for three-quarters of a century and has, in the meantime, seen a massive increase in global prosperity that has produced equally massive social change. The European Union was created as an antidote to the nationalism that had led to the world wars and in that respect has been successful beyond all hopes. But Russia’s invasion of Ukraine augurs more disarray and violence ahead.