Few of us in the modern West expect that our families will dictate our marriage choices, provide us with jobs and set us up with somewhere to live — an ordinary pattern for our ancestors and still common in much of the world. This has necessarily entailed some growth of the state to pick up some family functions, since the elderly, the ill and women with small children are often not viable economic units by themselves.

That this is generally a good thing is more arguable, but like most of us, I am happy to argue it. Societies that depend too heavily on kinship ties risk falling into what political scientist Ed Banfield called “amoral familism,” in which the good of the family becomes the only end anyone recognizes. This is oppressive for individuals, and disastrous for the larger community, because mistrust and nepotism stifle economic activity and make it impossible for neighbors to work together for the common good.

Liberalism’s triumph means fewer people than ever live in those conditions. And yet triumphing armies often have difficulty finding the natural stopping point of their expansion.