On the syllabus of my Econ 101 class was Paul Ehrlich’s The Population Bomb.  This being a year or two after the book’s publication, our class discussions weren’t debates about the veracity of the book’s thesis:

In the 1970′s the world will undergo famines—hundreds of millions of people are going to starve to death in spite of any crash programs embarked upon now.

Instead, our sophomoric freshman discussions, instigated by the professor, revolved around how best to cope with the coming apocalypse whose inevitability was never questioned.

Faster than you could say hokum, Ehrlich’s unscientific, alarmist predictions had gone from typeset to conventional wisdom to The Truth that no amount of fact, or, subsequently, reality, could dislodge or debunk.

To wit: I recently overheard a man in a store lament the “catastrophic destruction” that human beings were doing to the earth, and opine that it would be “the best thing possible” if people went the way of the dinosaurs.  Unable to resist, I asked, “What does it matter how pristine Earth is if no one’s here to enjoy it?  Then it’s just another uninhabited planet.”  “Well, that’s a homocentric point of view,” he tsked.

In truth, every country has a lower fertility rate than it used to; and in most of the developed world we’ve stopped procreating well enough to maintain replacement rates of population.

The cultural, financial, and political consequences of this unprecedented phenomenon are more profound than you might imagine—think: sclerotic, dying civilizations—and they’re laid out with precision in Jonathan V. Last’s terrific new book, What to Expect When No One’s Expecting: America’s Coming Demographic Disaster.

Maybe because Last was such a tenacious and meticulous researcher, and cites study after study (all indexed in the endnotes) to explain how and why we went from baby boom to baby bust, What to Expect doesn’t seem like a doom-and-gloom tome.

Nor is it preachy/moralistic.  It’s actually breezy, full of cool facts and anecdotes that you can drop at your next cocktail party.  (Did you know that Genghis Khan has 16 million living descendants—more, by far, than the Hebrew patriarch Abraham? Or that the Russians today have a lower life expectancy than they did in the 1950s?)

Quite apart from the reading pleasure and useful, even critical, information imparted, Last’s book offers an ancillary benefit in the way that it makes liberal heads explode exposes one of the major fissures between the left and the right.

What Last has described are, in essence, the consequences of liberal ideas cum mores cum policies enacted over the last 50 years.  And it’s just not fair, you see, that they might have done damage rather than lead to unqualified enlightenment (unfairness being the sine qua non of modern liberalism).

So rather than engage the substance and conclusion of Last’s text, liberal critics construct straw man arguments of the kind that President Obama excels at (well described by Professor Jacobson: “exaggerated and misleading characterization of Republican proposals in order to make Obama’s own policy seem like the only reasonable choice”).

For instance, Amanda Marcotte in Slate: “The reader is left with the feeling that the only solution to save capitalism is to clip the wings of half of the population so they can spend more time laying eggs.” This contains as much truth (none) as Ruy Teixeira’s accusations in The New Republic that Last is anti-immigration and anti-daycare; or his reliance on projections from that stalwart of demographic science, the United Nations, to counter Last’s claim that the world’s population will contract.

During the presidential campaign, I was struck by how casually some elites expressed a measure of revulsion for the number of children the Romneys (and, in general, Mormons) have—as though big families are a relic of some pre-rational age.  And I remember wondering whether a couple who’d chosen five abortions instead of five kids would have come in for the same criticism.  Is that fair?