This was a comment on CF’s recent post on polygamy, but it seemed to make more sense as its own post
I think the most effective argument against polygamy divorces the consideration entirely from the individual perspective. It argues that, even if polygamous relationships were completely fair (or just as likely to be fair as monogamous ones), they still have a corrosive effect on society. Like most things, Jon Rauch (Lure hero) said it best in this Reason column:
“The second crucial word is “polygyny.” Unlike gay marriage, polygamy has been a common form of marriage since at least biblical times, and probably long before. In his 1994 book The Moral Animal: The New Science of Evolutionary Psychology, Robert Wright notes that a “huge majority” of the human societies for which anthropologists have data have been polygamous. Virtually all of those have been polygynous: that is, one husband, multiple wives. Polyandry (one wife, many husbands) is vanishingly rare. The real-world practice of polygamy seems to flow from men’s desire to marry all the women they can have children with.
Moreover, in America today the main constituents for polygamous marriage are Mormons* and, as Newsweek reports, “a growing number of evangelical Christian and Muslim polygamists.” These religious groups practice polygyny, not polyandry. Thus, in light of current American politics as well as copious anthropological experience, any responsible planner must assume that if polygamy were legalized, polygynous marriages would outnumber polyandrous ones — probably vastly.
Here is something else to consider: As far as I’ve been able to determine, no polygamous society has ever been a true liberal democracy, in anything like the modern sense. As societies move away from hierarchy and toward equal opportunity, they leave polygamy behind. They monogamize as they modernize. That may be a coincidence, but it seems more likely to be a logical outgrowth of the arithmetic of polygamy.
Other things being equal (and, to a good first approximation, they are), when one man marries two women, some other man marries no woman. When one man marries three women, two other men don’t marry. When one man marries four women, three other men don’t marry. Monogamy gives everyone a shot at marriage. Polygyny, by contrast, is a zero-sum game that skews the marriage market so that some men marry at the expense of others.
For the individuals affected, losing the opportunity to marry is a grave, even devastating, deprivation. (Just ask a gay American.) But the effects are still worse at the social level. Sexual imbalance in the marriage market has no good social consequences and many grim ones.”
He goes on to detail the debilitating knock-on effects of having a bulge of superfluous unmarried males (seriously, everyone should just read the article). I personally find this bit quite persuasive (and we have seen these effects here in the US, on a small scale, with the “lost boys” the FLDS communes regularly excrete out into neighboring communities). However, this line of argument are unlikely to sway lifestyle liberals and hard-core libertarians (the sort who want to abolish drug laws or prostitution laws), which is why Rauch’s formulation is so effective. Polygamy does not expand the freedom to marry; it restricts it. Every polygamous relationship directly denies someone else the ability to marry. Under socially or legally enforced monogamy one is virtually guaranteed a mate, if they so choose, no matter their station or wealth. This is why the republics of Rome and Greece* were predicated on squelching the practice of formal polygamy: to at least facially suggest equality amongst men.
Thus it is frustrating when people like Drs. Ryan and Jeffa (Lure interlocutors) advocate polygamy or at least less restrictive monogamy with references to biology and individual rights. The biological business is largely true but irrelevant (all of civilization is predicated on resisting deleterious natural impulses), but the appeal to individual freedom is so gallingly myopic. They take a blinkered view of individual agency , in which all that matters is that any one person, in the abstract, can do as they please so long as they do not directly harm others. In so doing, people who cleave to such a narrow view of the Harm Principle overlook how individual actions, taken in the aggregate, alter norms and society and, ultimately, cause more harm and impinge further on liberty than the original sanctions they sought to overturn. I am reminded of a line from Ross Douthat (Lure agitator?) about the difference between liberals and conservatives:
“But this is what conservatism is, in the end: The belief that there’s more to a flourishing society than just the claims of autonomous individuals, the conviction that existing prohibitions and taboos may have a purpose that escapes the liberal mind, the sense that cultural ideals can be as important to human affairs as constitutional rights.”
Too true. On the topic, I am agnostic to Rauch’s proposition that decriminalization and renewed social sanction is the best method to combat polygamy. On one hand, its Jon Rauch (Lure hero) and its reasoning is seductive. On the other hand, it seems a tad too clever for its own good and might end up weakening, rather than reigniting, the social sanction against polygamy (overturning sodomy laws did not necessarily make for a strong firebreak against gay rights, to take a not entirely analogous example).
*Doing my best VDH here