The argument all along as been but what about polygamy? I've written on my view regarding this which is polygamy should also be legal if it's consenting adults. I recognize polygamy has been misused to force children into marriages with old men who can afford multiple wives and pushing out the young men from the community. That does not mean the state has a legal right to block two men and one woman from deciding they want to bind themselves together legally. To me, it does make sense so long as it's adults and no coercion is involved.
Then I read this as it is a hot button issue again as we are going to have our very divided Supreme Court weigh in on this with the religious right wing of it voting one way and the religious (yes, they are all religious as best I know it) left wing voting the other. Which could mean the right will win-- not necessarily to force states already allowing gay marriage to change their laws, but just not to make the whole country recognize it as a Civil Rights issue.
So I would be in favor of making polygamy legal with the above caveat-- consenting adults. I also think polyamory is a real possibility for some people where a man falls in love with two women and would like to have a binding relationship with both-- not in that case legally but emotionally.
The irony of the ones who are against gay marriage or polygamy is that these relationships have existed all along. They are just hidden. So a couple have a very good friend who lives with them but the friend has no rights. Within the three, they know she does, but to the outside world, she does not. There have been famous combinations where that has likely been the case. Is the extra woman for the wife or the husband? Only they would know and it's really only their business. Except for legal reasons it can become important to the State. It gives rights. That's what these relationships are really all about once they become a contract.
They said they think the above case will fail and the 'family' will be forced from their home. The self-righteous ones forcing this may be on their own second or third marriage, maybe with multiple affairs along the way, but that's not the issue is it? It's all about looking right...