There are reasonable criticisms that can be made of Sarah Palin, both as governor and a vice presidential selection. Yet little of what we have seen in the last six days has been either reasonable or critical (in the traditional sense of the word). Instead, much of the left and many in the media simply lashed out at Palin, particularly at her family.

And not only the fringiest parts of the political fringe: A writer at the Washington Post attacked Palin for the fact that her seventeen-year-old daughter was going to have a baby. A writer for The Atlantic openly questioned whether or not Palin’s four-month-old baby, who has Down’s Syndrome, was actually hers. The utterly unfounded suggestion was that the baby was Palin’s daughter’s and that the governor had faked her pregnancy. Proof of the baby’s birth was demanded.

Again, we are not talking about an anonymous blogger at Daily Kos—this is the commentary from the Washington Post and The Atlantic Monthly . And there was more—much more—where that came from.

So why? What is it about Sarah Palin that convinced so much of the left to objectify and assault her so quickly, and with such manifest maliciousness? There are many reasons, but four of them stick out in particular, each having to do not with Palin’s politics, but with her family.

1) Trig Palin’s Down’s Syndrome is a challenge to their ideas about what represents worthwhile life. The fact that this Down’s baby was carried to term and not aborted is statement that his life has the same value as all life. This is an idea with which the left vehemently disagrees. Here is the Washington Post’s Ruth Marcus discussing her own opinion of Down’s babies in an online chat earlier this week:

I had my children at ages 37 and 39, old enough that the risk of Down syndrome was elevated, as it was for Palin, and my doctor recommended amniocentesis. Had the results indicated any abnormality, I have little doubt that I would have made a different decision than did Palin.

As such, the left sees Baby Trig as a provocation. Note today the commentators complaining that Trig has become a “prop” for Palin’s candidacy simply because the family took turns holding the four-month-old in public last night. (Perhaps these observers simply have no understanding of how infants are handled and cared for.) Instead of being viewed as just another baby, Trig is seen by the left as a little Terri Schiavo—an assertion of the value of all life and an affront to their belief that there are differences in what constitutes meaningful life.

2) Which leads, of course, to abortion. Palin’s family is a double-rebuke to the culture of abortion. First, there’s Palin’s decision not to kill Trig because he has Trisomy 21. Then there is seventeen-year-old Bristol Palin’s decision to not to kill her baby.

Contrast this with Barack Obama’s statement that he would keep abortion legal so that if one of his daughters were to “make a mistake, I don’t want them punished with a baby.” This statement is freighted with meaning: Obama views out-of-wedlock pregnancy as a mistake (which is sensible); he views such a resulting baby as punishment (which is less so); and he has strong feelings that should such a situation occur, he would not want his daughter to carry the baby to term. It is, objectively speaking, a pro-abortion statement.

3) Then there are Palin’s religious views. She is a lifelong Christian who belongs to an evangelical church. No further explanations should be needed about the provocations which emanate there from.

4) Finally, there’s the fertility. The Palin family’s five children would have been unexceptional forty years ago, but today constitute something of a fertility freak show. They’re the type of people for whom the epithet “breeder” was invented. The U.S. fertility rate sits just below the replacement level and is only that high because of the greater fertility of Hispanic immigrants. According to the most recent census data , only 1.1 percent of non-Hispanic white women bear five or six children over the course of their lifetime. By contrast, 22.5 percent of these women never reproduce. The percentage of childlessness among women rises in a straight line with educational attainment.

Why the worry about this? First, there’s the fact that few of Palin’s tormenters can understand the fact of her large, traditional family. That is certainly not the way in which they have structured their lives.

Second, there is the left’s long-standing concern about overpopulation, which has become a staple of modern environmentalism, beginning with Paul Ehrlich’s 1968 best-seller The Population Bomb . Ehrlich preached a Malthusian near-future in which hundreds of millions would perish by famine as the world’s unchecked population growth spiraled to infinity. As it happens, Ehrlich’s predictions were entirely incorrect: Not only has increased food production reduced famine to a weapon of political conflict, but the world’s population growth has slowed to a crawl. Fertility rates around the globe are falling and world population will peak around nine billion by 2050. From there, we will experience population contraction.

But Ehrlich’s prognostications never fell far out of favor, particularly with environmentalists who take it as an article of faith that the planet is already overcrowded. To them, the prodigious Palin family is surely seen as taking more than its fair share.

And finally, there is the concern that the amped up fertility of people such as the Palins will lead to a less progressive future. In an influential 2006 essay in Foreign Policy, demographer Philip Longman warned of the “Return of Patriarchy” as religiously orthodox and fundamentalist populations were reproducing at much higher rates than post-modern and secular populations. The result, Longman worried, will eventually be a return to a less politically and culturally progressive era.

As you can see, each of these facts about Sarah Palin touches upon deep sources of antagonism. Her opponents quickly intuited that the particulars of Palin’s story, on their own, stand as challenges to some of the most integral parts of their worldview, whether or not she ever makes them explicitly.

It isn’t any of Palin’s specific policies or ideological beliefs which have so antagonized the liberals (although they surely dislike her for policy reasons, too). They simply hate her for who she is.