I asked my parents one time when I was visiting why they felt like gay marriage was ok since they were supposedly Christians. They both said the same thing, "I just don't care. It doesn't effect me so why should I care?"
I think that says a lot about American society in general. We've become such a "me" society that if something doesn't effect "me" then it doesn't matter. I think it's a little narcissistic if you ask me.
I would like to point something out though. A marriage licence is a legally binding document. It has a definition. When heterosexual couples married 5 years ago, marriage had one definition. Now, it has 2. One could argue every single marriage licence is now void because the definition of marriage has changed and should one of the partners decide they don't want any contract with their name on it that uses the word "marriage" that now can mean two gay dudes, they should be able to walk away from it as a null and void contract. Any time you change the meaning of a contract retroactively you void the contract as it is written.
Before you say it doesn't matter, think about it like this. When they got married, if they were alone and told someone they were married, they automatically knew it was an opposite sex partner. Now they have to specify.
Food for thought.
I don't see why they have to specify. For example, I get called a "dude" all the time on this board because it's for whatever reason assumed that I must be a guy. Am I obligated to "fix" the mistaken thinking of the poster in question? No. Sure I can if I wish, but I don't have to. More importantly though, does it change the "worth" of my post if I am a female and not a male?
Most folks figure this kind of shit it out through conversation or don't ever figure it out and it doesn't matter to the conversation at hand. When someone says they're married I don't stop to ponder if they're straight or gay, any more than I stop to ponder if their wife/husband has blond/brunet/brown/black haired. But then again, I tend to see folks as "equals," as it were, regardless because I don't have some odd need to sort them out into race, religion, and sexual orientation/identity to determine their "moral status" while talking to them.
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That said, on the matter of polygamy, while I support it personally, I can see there being a legal interest in the complexities of divorce, child custody, inheritances, insurance, and tons of other family related law cases.
Though situations like that exist even without any intent of polygamy; in the example of my divorce for example, my second husband has raised my son as "dad" pretty much since before my youngest could crawl - if I were to have died, it could have been an emotional double wammy for my son if my exe wouldn't allow him to retain a relationship with dad 2 for whatever reason. (In my case that would not have happened because my ex and I, and our 'new' wife/husband, have the equivalent of an "open parenting" arrangement heh but I can see it happening.) As far as the law is concerned /only/ the biological parents have any say in anything, step-parents (which is the closest equivalent to a second wife/husband) are basically given zero consideration on the "positive" side of things (they are given consideration if they have negative traits or w/e in custody cases though) thus in a situation of multiple wives/husbands, the law would have to default to bio children's parents which could be devastating for children involved - losing their step brother/sisters, plus stepparents who they see as parents regardless of biology. (I believe that's the safety net they talk about?)
In any event, there is a huge legal mess that'd have to be sorted out before polygamy could be made "legal," so I don't think it's "morals" or "the definition of marriage" that restrict it. That said, I do think it will become legal in the future given the number of non-Christians in the country (and more coming in daily) who have a legit religious reason to practice it; we're just going to have to do some legal juggling to figure out the details of it all. Like will ACA demand that insurance companies cover second wives and shit like that.
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Incest, I just don't see becoming legal, even if one or two couples can push their cases through the courts because of a non-compelling reason for state restriction, I do not see there being enough people interested to have enough cases to push it to the supreme. Even if the SCOTUS ruled that x brother and their brother can get married, there's not enough incest people in the country, or any one state, to push for any kind of national legalization. Typically incest occurs when a population is small and trapped, or it occurs through arranged marriages to maintain control of family wealth, these are not really things that relate in America, 99.9% of us are too mobile and too aware of our "rights" to not choose our own husband/wife outside the family. I think society would have to regress to an "ownership" status of people for this to be more than a blip of oddity (like the person who can squeeze milk through their eye glands; sure it happens, but it's rare.) I guess I look at it like if some guy wants to marry his sister then whatever, I find it odd, but w/e. I personally find following a religion "odd," anal sex is "odd" to me, breast play is "odd" to me, doesn't mean others can't enjoy/do it though.
I'm a "too each their own thing" kind of person and I have no need nor desire to tell others what's "right" or "wrong" in their personal relationships. Kind of like I don't particularly like my eldest boy's long time girlfriend, she's a snobby little ***** who I'm pretty sure is going to break his heart, but I support his decision to continue his long-standing relationship with her, even knowing that they'll probably get married, because in the long run, ultimately, as long as my son is happy then I will be happy for him/with him. Bottom line for me is that even as a parent, I do not have the "right" to tell my son who he can and cannot marry, why in the hell would I have the right to tell a stranger who they could and could not marry? I personally have to respect /his/ choice, and /their/ choice, as adult American's who have free will and their own opinions, feelings, and tastes. It's not my place to decide for someone else, and that's pretty much the basis of where I stand with the entire issue of marriage "restrictions." ~shrug~