Assemblyman Mark Leno, D-San Francisco, who has pushed for same-sex marriage in California, noted "a unique nature of a relationship with two. If you go beyond two, you can't draw a line anywhere else that isn't arbitrary." I agree, but the Canadian study gives me pause. The authors use a very American argument: that adults already are living in de facto polygamous relationships, so why make their arrangements illegal?

 The answer is that even if authorities cannot and should not jail adults for group cohabitation, the state should not extend legal protections to those unions.

 Extending marital protections to same-sex couples bestows equality. Extending protections to unequal unions protects inequality.

 The Washington Times interviewed polygamous Mormons who argued they lead happy, harmonious lives. That may be, but the practice is poison for cultures at large. Rich men marry many wives. Poor men do not. Women have few opportunities and limited rights. It can't be good for the kids. Consider polygamy's most famous son: Osama bin Laden, whose father sired 54 children with 22 wives.

  Many elites argue that Canada is 10 years ahead of America when it comes to gay rights. But when legal scholars are so progressive that they are willing to shove marriage back to the Stone Age, they reveal a culture with a death wish.

 American advocates for same-sex marriage may want to reconsider supporting civil unions in lieu of same-sex marriage. Or some way to limit marriage to two adults.