First off, that's odd given that the Utah attorney general's office explicitly states that law enforcement has no intention of focusing on enforcing those laws. (http://attorneygeneral.utah.gov/polygamy.html). I guess when you are flaunting it...
Second, the 'Utah Polygamy Law' is not merely a law, it article 3 of that state's constitution, included as a condition of statehood: (http://le.utah.gov/~code/const/htm/00I03_000100.htm)
First: -- Perfect toleration of religious sentiment is guaranteed. No inhabitant of this State shall ever be molested in person or property on account of his or her mode of religious worship; but polygamous or plural marriages are forever prohibited. .Third, I happen to come down on the polygamist's side on this one. Here's how:
A. The Brown families have between them 1 civil marriage. The rest are religious marriages only.
B. While I admit that the intent of the Utah Constitution Article must have been to foreclose this loophole, I am not sure it can. Even if you say that the article prohibits religious polygamous marriage in addition to civil polygamous marriage, nothing prevents a man from simply taking up with several women, siring children with them and cohabiting. No stated marriage of any kind. There is no prohibition against "practical polygamy" or what I guess we'd consider polyamory.
C. As is clear from the paragraph above, the only thing the state must be targeting is religious polygamous marriage as it already makes bigamy illegal in the civil context. That raises some serious freedom of religion issues.
D. And yet, none of that forms the center of the current legal challenge, which relies on Lawrence v. Texas, in which two gay men were targeted by a neighbor who phoned in a fake weapons charge to get the two caught in flagrante delicto (don't you just love that phrase?). The Supreme Court held that laws targeting the sexual proclivities of consenting adults violate the due process and equal protection clauses of the U.S. Constitution.
Nice choice. Seems pretty clear cut that if you cannot make a threesome illegal for a man, married or not,you shouldn't be able to make the same act illegal just because the man claims a spiritual relationship with both women. (That would, for example, invalidate a lot of the early 1970s).
But, I can hear the nabobs nattering, this isn't about sex, it is about the rest of the relationship - the holding out oneself as head of many households. For that we go back to religion. How, forsooth, is being the head of multiple households of unmarried women different from a man who has multiple children out of wedlock and visits them all? Indeed, if that man were as involved as this man, we'd applaud him. Which means what we really don't like is the religion. See Article 1.
E. And a postscript: There are many things to dislike about polygamous communities in the U.S. as it pertains to individual rights, child abuse, and so on. The thing is, much of that is not a function of polygamy per se, but of the oppressive communal norms that attend it. Utah and other states focus on those violations as they should. Look, we don't outlaw rap or first round NFL draft pick-ed-ness or NASCAR or islam or fundamentalist christianity or ultra orthodox judaism or first generation immigrants because the incidence of domestic violence is higher in those communities. I admit there are efforts on that last one. We target the action itself and lay down a rule of law. The communities in question learn to respect that law and come to prize it. That is what makes America great.