Finally, there’s been a broader cultural shift away from a child-centric understanding of romance and marriage. In 1990, 65 percent of Americans told Pew that children were “very important” to a successful marriage; in 2007, just before the current baby bust, only 41 percent agreed. (That trend goes a long way toward explaining why gay marriage, which formally severs wedlock from sex differences and procreation, has gone from a nonstarter to a no-brainer for so many people.)

Government’s power over fertility rates is limited, but not nonexistent. America has no real family policy to speak of at the moment, and the evidence from countries like Sweden and France suggests that reducing the ever-rising cost of having kids can help fertility rates rebound. Whether this means a more family-friendly tax code, a push for more flexible work hours, or an effort to reduce the cost of college, there’s clearly room for creative policy to make some difference.

More broadly, a more secure economic foundation beneath working-class Americans would presumably help promote childbearing as well. Stable families are crucial to prosperity and mobility, but the reverse is also true, and policies that made it easier to climb the economic ladder would make it easier to raise a family as well.

Beneath these policy debates, though, lie cultural forces that no legislator can really hope to change. The retreat from child rearing is, at some level, a symptom of late-modern exhaustion — a decadence that first arose in the West but now haunts rich societies around the globe. It’s a spirit that privileges the present over the future, chooses stagnation over innovation, prefers what already exists over what might be. It embraces the comforts and pleasures of modernity, while shrugging off the basic sacrifices that built our civilization in the first place.

Such decadence need not be permanent, but neither can it be undone by political willpower alone. It can only be reversed by the slow accumulation of individual choices, which is how all social and cultural recoveries are ultimately made.