Posner on Polygamy
It is a little odd that polygamy is illegal while other marriage practices aren’t (in some states). But is polygamy a bad thing? While it’s an empirical question, Posner offers a good argument against it:
My view is that polygamy would impose substantial social costs in a modern Western-type society that probably would not be offset by the benefits to the parties to polygamous marriages. (For elaboration, see my book Sex and Reason (1992), particularly Chapter 9.) Especially given the large disparities in wealth in the United States, legalizing polygamy would enable wealthy men to have multiple wives, even harems, which would reduce the supply of women to men of lower incomes and thus aggravate inequality. The resulting shortage of women would lead to queuing, and thus to a high age of marriage for men, which in turn would increase the demand for prostitution. Moreover, intense competition for women would lower the age of marriage for women, which would be likely to result in less investment by them in education (because household production is a substitute for market production) and therefore reduce women’s market output.
Here’s even more.