Also, gay "marriages" and relationships are empirically proven to last longer than those of average heterosexual ones.
Miyabi, I've seen statistics that say the opposite, and a higher incidence of domestic violence as well. It's easy to talk about how studies have been done without giving any proof.
Can Baptists determine if the Catholic church can make women priests? Then why do Baptists get to determine if Unitarians marry gay and lesbian parishioners?
CthulhuKefka, is anyone doing that? This isn't about what churches do with their members. It's about legal recognition, what word is used to apply to that legal recognition, and how that word is defined.
Also, interracial marriages were never universally banned in the U.S. Quite a few states never had miscegenation laws, and many states repealed them in the 1800s. Society was not united on the issue, and where the laws were in effect, they made interracial marriage illegal and arrested those who practiced it. They didn't say it wasn't a marriage; they said it was an illegal marriage. There's a difference. The same-sex marriage issue is not the same. Same-sex marriage does not fit the definition of marriage universally historically accepted in our society. It was taken as a given that marriage included a man and a woman. The states still added on other restrictions after that, within their right to do so: 3. You can't marry someone who's too closely related to you. 4. You can't marry someone who's too young. 5. You can't marry someone who's currently married to someone else. 6. You can't marry someone if you are currently married to someone else. These are all restrictions to marriage rights which states have enacted with no problems.
But even before those 4 are the two inherent marriage rights restrictions that were taken as a given from the start. 1. You can only marry someone of the opposite sex from you. 2. You can only marry someone who agrees to marry you.
These six restrictions on marriage have been universally applied throughout the history of our country. There are minor variations on what "too young" or "too closely related," but all states have a set standard defining that. Mormons and other small groups tried breaking restrictions 5 and 6, but were rejected all the way to the Supreme Court. Societies that preceded ours did not always follow restriction 2, but it's been followed for several hundred years.
The granddaddy of them all is restriction 1, so much so that it's by default included in what the word "marriage" itself means. If you drop that restriction, you remove a large percentage of the significance of the word.