DOMA and Prop 8. Both History.

[kandrathe]

I assume we have a similar smell test to tell whether monogamous marriages are "really consenting"?

It's pretty hard for the authorities to sanction or prohibit any relationship -- but, adults should be free to make their own decisions. I believe the stigma's against group marriages are societal norms, not based upon any practical theory of harms.

In the US, when looking at the behavior of those having many relationship partners outside of marriage, polygamy is an obvious choice of some (for both men and women), but one that is outside the cultural norm. Women tend to be more serial monogamists, but again that may be influenced by norms. Don't look at the fundy Mormans -- that is antiquarian. Look at the how the society is engaged in sexual relationships. In the US, 1 in 5 women have children from multiple fathers.

The law enforces monogamy.