I think you're right Zec. Didn't the same thing recently happen in Canada? The way I see it, polygyny is the philosophical polar opposite of the direction our society has headed and I'd be surprised if they open the door to it. They'll probably claim it's inherently abusive as it promotes inequality, which is the great "sin" of our day and age. Some people are more equal than others, you know.
Untold Glory, the government should ideally stay out of marriage. However, I fear that it's a poisoned pawn. If marriage ever ceases to be recognized then we will no longer belong to families, we will be individuals in the eyes of the law. This means increased license for government intrusion into our personal affairs. Wives could be compelled to testify against husbands, licenses could be required to work with children including your own, inheritance would pass more readily to the state, etc. It's a slippery slope indeed.
I'm becoming more firm on the opinion that the attack has been on Christianity itself all along, this time through vehicle of the destruction of the concept of marriage. Of course, the recent ruling is only one of many moral steps downward as adultery, divorce, fornication, drunkenness, and more are not only legal, but they rarely raise eyebrows even among Christians anymore.