The new birth rate numbers are out, and they're a disaster. There are now only 59.6 births per 1,000 women, the lowest rate ever recorded in the United States. Some of the decrease is due to good news, which is the continuing decline of teen pregnancies, but most of it is due to people getting married later and choosing to have fewer children. And the worst part is, everyone is treating this news with a shrug.

It wasn't always this way. It used to be taken for granted that the best indicator of a nation's health was its citizens' desire and capacity to reproduce. And it should still seem self-evident that people's willingness to have children is not only a sign of confidence in the future, but a sign of cultural health. It's a signal that people are willing to commit to the most enduring responsibility on Earth, which is raising a child.

But reproduction is also a sign of national health in a more dollars-and-cents way. The more productive people you have in your society, the healthier your country's economy. It's an idea that was obvious back in the 17th century, when economist Jean Bodin wrote "the only wealth is people."

Today we see the problems wrought by the decline in productive populations all over the industrialized world, where polities are ripping each other to shreds over how to pay for various forms of entitlements, especially for old people. The debates play out in different ways in different countries, but in other ways they are exactly the same. That's because they are ruled by the same ruthless math: The fewer young, productive people you have to pay for entitlements for old, unproductive people, the steeper the bill for the entire society becomes. This basic problem is strangling Europe's economies. And while the United States is among the least bad of the bunch, it is still headed in the wrong direction.

It doesn't have to be this way. While the evidence for government programs that encourage people to have more children is mixed, the fact of the matter is that in contemporary America, 40 percent of women have fewer children than they want to.

And there are plenty of policies that could help close that gap, whether from the left or from the right. Not just pro-maternity policies, but also policies that encourage healthy child-rearing, like child tax credits, family savings accounts, and tax-free children savings accounts. Or education reforms that would make fewer parents feel that they have to pony up for private school to give their kids a decent shot at life. Perhaps one of the biggest things we could do is to reduce the countless state and local regulations that make housing expensive.

But put policy aside for a second. The United States literally exports more oil than Saudi Arabia and has the world's top expertise in both renewable and traditional energy forms. It is the world's biggest food producer and a gargantuan country with very little density. There is no reason for the United States to have a weak birth rate — and it is a national emergency that it does.

Yet no one seems worried. And that might be the biggest worry of all.