On Tuesday, Justice Scalia asked when gay marriage became unconstitutional. This morning, I came up with a good answer. This is why I'm not a lawyer.
Gay marriage became unconstitutional when scientists realized that homosexuality is not a mental disorder, which I believe was in the early 1970's* (though I could be off by a bit. Perhaps they figured it out in the 1960's but it only got taken out of the DSM in the early 1970's.) Before that, it would have been unreasonable to allow gay people to marry, because people with severe mental disorders do not have standing to marry.
Since then, we have seen homosexual behavior in almost every species of animal we have studied, we have discovered a gene that causes androphilia (a strong attraction to men) in both men and women, and we know that the more sons a woman has, the more likely her younger sons are to be gay because of a hormone she emits more of during each successive pregnancy. So we know that homosexuality is natural. We have seen one after another group that formerly claimed to "cure" people of homosexuality admit that orientation can't be changed. So we know that it is immutable. And we have been through the plague of AIDS that permanently changed gay culture and an entire generation growing up without the idea that homosexuality is a mental disorder.
It was when my generation, born in the 1970's, came of age that the movement toward legalizing gay marriage began in earnest, and that's no accident. People my age were the first to come out in high school, the first to come of age post-AIDS, and the first to grow up knowing that homosexuality is just something that comes up in the gene pool about 3% of the time. It's only natural that it would be people my age who would expect to marry their partners.
So that's your answer, Justice Scalia. The day homosexuality came out of the DSM, gay marriage should have been legal because gay people are people and therefore eligible for equal protection under the law. Once we stopped "protecting" them from their "mental disorder," we should have given them equal rights.
Perhaps we can be forgiven for not giving those rights instantly, because most people then thought that gay people were different in the way they formed relationships. They always had been, of course, because they had to be. When the love you feel is classified as sickness, you don't date in public. But once a generation grew up knowing they weren't crazy, they expected and asked for the same rights straight people have. From that point on, we've been wrong. Just plain wrong. And now the Supreme Court has a chance to set it right.
So that's your answer, Justice Scalia. Now do you know how to rule on this?
*UPDATE 3/29/13: It was 1973. Thanks, Andy Drouin, for leaving that comment. So, 1973 is when it became unconstitutional. Got it, Justice Scalia? 1973.