Who's Afraid of Low Birthrates?

Yglesias wonders, in the context of the Georgian Patriarch's pro-natalist baptism policy:

Less clear to me is why so many people seem concerned by the specter of low birth rates. Historically, low levels of population are associated with high average living standards. That should be less true in the modern world where we're not as dependent on agriculture for our economic activity. But the logic hasn't completely vanished. If there were dramatically fewer people in the United States it would be much more realistic for us to all be eating free-range organic grass-fed beef. And even amidst a real estate bust, the country is far too crowded for a middle class family to afford a spacious residence in the most desirable markets such as San Francisco or Manhattan.

As appealing as the vision of a depopulated America where we all get to live like Manhattan gourmands may be, I think it's worth taking note of this Ezra Klein post from the very same day, which cited Angela Merkel explaining her aversion to the kind of big-ticket stimulus that most American liberals are pining for:

It is not, she pointed out, simply a philosophical difference. Borrow and spend today, repay down the road, is a particularly difficult proposition for a country with a shrinking population, she said.

"Over the next decade we will undergo a massive demographic change, and, therefore, borrowing is a greater burden for the future than in a country with a much more continuously growing population, as in the United States of America," Mrs. Merkel said.

Now perhaps these are overstated fears - and of course Ezra's response (and Matt's, in a related post) is that this can all be solved with higher immigration rates. But with apologies to Harry Truman, it doesn't seem unreasonable to think that if you want to live like a Whole-Foods-shopping San Franciscan Democrat, you need somebody, somewhere, to procreate like a megachurch-attending Republican.