Right, it’s not like the Mormons practiced polygamy or anything.
Oh, wait…
So, why did we outlaw polygamy? I know my own ancestors left Utah to stop getting pressured into taking on a second wife, but it was still legal then and it was just a personal choice. Why was it outlawed? What’s changed that would make it a better idea now?
Ethilrist: there are more social and legal protections in place now than in Brigham Young’s day. In those days, women had very limited legal protections against being married without their consent. Marriages (both single and multiple) were largely compulsory.
Our legal system – and our society – is not yet perfect. I’m sure that some people are still under huge duress to get married, even when it isn’t what they really want. But the major failings of the system have been corrected today.
Not that banning the practice among Mormons was really about protecting women. It was more a matter of cultural prejudice against the practice in most other demographics, and clearing the consequent difficulty in Utah becoming a state.
I don’t think same-sex marriage will lead to acceptance of polyamory, though I do think that the same shift in attitudes about sex and relationships that is helping same-sex marriage along will sooner or later do the same for polyamory. But either way, I don’t see that as an argument against same-sex marriage.
Moreover, as DrFidelius pointed out here and countless other posters on previous threads, poly marriage differs from dyadic marriage in a way that’s not wholly parallel to the differences between same-sex and different-sex marriage.
(And yeah, Dan Savage isn’t in favor of compulsory or default monogamy, but he only grudgingly accepts infidelity in an extremely circumscribed set of circumstances.)