It wasn’t difficult to find words of the prophet Brigham Young about the role of government in defining marriage. What will be difficult is for the Church to reconcile its position on Proposition 8 with these teachings of one of its greatest leaders, while he was the President of the Church and God’s mouthpiece for His faithful on Earth. These are written in the Journal of Discourses, Vol. 11, pp. 266 ff.
Who knows but the time will come when the inquiry will be made in Washington, by the President, by the Congressmen: “Are things any worse in Utah than in Washington: than they are in New York? or in any State of the Union? are they more unvirtuous, are they more disloyal to the Government? But then there is polygamy.” That has nothing in the least to do with our being loyal or disloyal, one way or the other. But is not the practice of polygamy a transgression of the law of the United States? How are we transgressing that law? In no other way than by obeying a revelation which God has given unto us touching a religious ordinance of his Church. And the anti-polygamy law has yet to be tested, as to its constitutionality, by the courts which have jurisdiction. By and by men will appear in the departments of the Government who will inquire into the validity of some laws and question their constitutionality.
Above, Young implies that the anti-polygamy law did not need to be obeyed as it had not yet been tested in courts with appropriate jurisdiction. One would further infer from this that Young would be (justifiably) concerned if an anti-polygamy law were upheld as constitutional in a court of competent jurisdiction.
Young then immediately continues (emphasis added),
Marriage is a civil contract. You might as well make a law to say how many children a man shall have, as to make a law to say how many wives he shall have. It would be as sensible to make a law to say how many horses or oxen he shall possess, or how many cows his wife shall milk.
Young opposed a law that stated that a man could only marry one woman — not a far cry from “marriage shall be defined as the union of one man and one woman.” The words of this latter-day prophet are unequivocal: marriage is a civil contract. It is not a function of the government, and government’s role in protecting the “traditional meaning of marriage” didn’t carry a whit of weight to Brigham Young. Clearly, the tradition cited by LDS opponents of same-sex marriage is not as old as their relatively young church (no pun intended).
Young meant that if a man wished to marry five women, and those women desired to enter into those marriage contracts, they should be entitled to do so without the interference of the government. But this logic also means that if two women wish to marry each other, those two individuals should be entitled to enter an equivalent civil contract that a man and a woman might wish to enter into. Young’s point is that the government should not make laws about individuals’ rights to enter into civil contracts.