Thank you; glad you asked.
The definition of marriage has most certainly changed over the “millenia” that the Justice mentioned. King Solomon’s definition of marriage, as cited, involved polygamy and many, many children born out of wedlock. He himself was born out of wedlock after his father’s affair with his mother Bathsheba. And Solomon was a well-respected wise jurist who handed down decisions widely accepted by his people.
Medieval European marriage was almost entirely about financial arrangements, and love was often scoffed at, as having no place in such arrangements, especially among the aristocracy. Love was for peasants or for mistresses. The greatest love stories of medieval and renaissance Europe were outside of marriage. Guinevere and Lancelot. Tristan and Isolde. Romeo and Juliet (her parents arranged for her to marry the Count Paris). Dante and Beatrice. When Wolfram von Eisenrach writes Parzival, and includes a love-match marriage, the world gasps, and, historians note, also begins to experience a change in the definition of marriage.
Henry VIII redefined marriage and divorce. Legally.
When arranged marriages went out of style in Russian Jewish culture, Tevye worried about Tradition but blessed his daughters anyway, in their new definitions.
The problems of unhappy couples, of unwanted children, of families in poverty, will NOT be solved by preventing some people from establishing stable homes. There won’t be fewer two parent families without a traditional definition of marriage because the people who aren’t married now, the heterosexual, procreating people, aren’t going to all of a sudden develop stable two-parent homes because we prevent other people from doing so. What, you think they’re going to say, wow, so few people can GET married now, we’d better step up to the plate? I’d better marry somebody I’m not that crazy about, after all the earth is underpopulated?
And as for the concern that people of a certain moral conviction will be marginalized as bigots because the world is changing without them, welcome to the world, people of moral convictions. I have been marginalized for my moral convictions for a very long time now, as my values are dismissed by the majority. A few days ago a Governor of a Great State of This Nation referred to my chosen educational discipline, my livelihood and my profession, as a “junk” degree. But if it would make him feel any better he should know that my late husband gave his health, his eyesight and his sanity (to paraphrase General Washington) to making the world richer for John Thune Merrill Lynch Pierce Fenner & Iggy, and ultimately Bank of America, so at least SOMETHING worthwhile once came out of this household.
There. You asked a hippie.