The infamous polygamist Kody Brown family of the TV show “Sister Wives” has done what conservatives (particularly Mormons) have feared would happen ever since the gay marriage debate began to take hold. They used the same-sex marriage rulings to argue the legality of polygamy.
The Browns have used this argument before in lower courts with some success. That includes the U.S. Supreme Court case of Obergefell v. Hodges, in which the court upheld the fundamental right of same-sex couples to marry, and Kitchen v. Herbert, the case that brought same-sex marriage to Utah. Turley also cites a Supreme Court case that decriminalized all gay sex as sodomy, Lawrence V. Texas.
In short, the Browns’ lawyer is arguing for the decriminalization or rejection of morality legislation. For the same reasons homosexuality was considered immoral and illegal, polygamy has as well. Now that the gay marriage contingent has convinced the world that this was an archaic belief, the polygamists want to make the same argument. If the argument on behalf of gay marriage is that any two people who want to be married should be allowed to do so, why can't polygamists legally marry? Polygamists don't marry one wife to another. They marry the woman to the man. It's still just a marriage of one woman to one man, but the man happens to also be married to another woman. If all parties are clear on the facts, using the gay marriage defense, why shouldn't it be legal?
"From the rejection of morality legislation in Lawrence to the expansion of the protections of liberty interests in Obergefell, it is clear that states can no longer use criminal codes to coerce or punish those who choose to live in consensual but unpopular unions," Turley wrote in his answer to Utah's appeal.