Polygamy legal until 1862.
Laws prohibiting interracial marriage overturned in 1967.
The first no-fault divorce law takes affect in 1969.
In 1973, Maryland becomes first state to define marriage as "between a man and a woman".
Rape within marriage becomes illegal in all 50 states in 1993.
In 1998, South Carolina is the last state to remove interracial marriage ban from state constitution.
2000-2006, time period in which most states alter their Constitutions to prohibit same sex marriage.
2004-2012, time period in which several states allow same sex marriage.
The "traditional" definition of marriage is actually pretty young.
History pokes holes in the notion of a "traditional" definition of marriage. Same sex marriage was practiced all the way back in ancient Rome, and even two different Roman emperors were married to same sex partners. It also has spanned cultures from China to Brazil. Marriage is a very artificial construct that has always been adapted to the dominant culture of a society.
What has truly limited same sex marriage has been the criminalizing of homosexual acts. It wasn't until 1962 that the first state decriminalized consensual homosexual acts in private. Rather than being a "laughingstock" the idea of same sex marriage would have been a felony during the 50s.
The existence of laws against same sex marriage throughout history are the best evidence that the "man and woman" definition has not always been as self evident as same sex marriage opponents would like people to think.
Further, it would greatly improve the basic sense of logic if certain narrow political camps would pay attention to the fact that a politically dominant way of doing things isn't the ONLY way to do things. The very same socially conservative notion of traditional marriage -- one man, one woman (preferably of the same religion) choosing a lifetime exclusive romantic, sexual, and economic partnership -- is itself a radical departure from much longer-lived traditions of marriage (like marriage-as-property transaction, marriage-as-real-estate-contract, marriage-as-means-of-keeping-pharaohnic-power-in-the-family (eew!), etc.).
Yet even during the respective reigns of dominance of each of those much older, much longer forms of tradition, it was still the case that other less-known practices did exist.
This basic disconnect -- in which that which is dominant is treated as "the" definition of something just because it is dominant -- is a hallmark of totalitarianism and fascism. Rather than make any attempt at rational engagement with other views and practices, those who appeal to popular prejudice and/or political dominance are in effect declaring open war upon all other ways of doing things. It is the approach so perfectly summed up by Bruce Campbell as Ash in The Army of Darkness;
"...Good? Bad? I'm the guy with the gun."
That's ultimately what the paleo-conservative appeal to bigotry with regards to marriage amounts to... "Good? Bad? We can outvote and outspend you...so you simply don't matter."
I've moved on to a better forum (scienceforums.net). Facts matter, and I don't have the time or energy for putting up with the pretense that they don't. PM me if you'd like me to get in touch with you when I'm done developing my own forum system, likely towards the end of 2013.