You draw the line at rights. If an action does not infringe upon the rights of another.. the state has no business restraining it.
If we allow same-sex marriage, should we also allow a brother and sister to be married? How about a mother and son? Father and daughter? A woman and a horse? Where does it end?
It ends at rights. If the participants are consenting adults of sound mind, the state has no business restraining their actions if they do not infringe upon the rights of others.
I will tell you where it ends: Marriage is a union sanctioned by God. It consists of one man and one woman (who are not related). That is the way it is, that is the way it should be.
The Mormons said God told them to marry more than one woman. Did you think the force of state guns should be utilized to prevent them from fulfilling their duty to God? God said it, I believe it, that settles it.
God gave you many personal commandments. But he only speaks to your involvement with other men via these words... "Love thy neighbor as thyself"... "Do unto others, as you would have them do unto you".
Apparently though, you apply your "that settles it" credo somewhat selectively.
It ends at rights. If the participants are consenting adults of sound mind, the state has no business restraining their actions if they do not infringe upon the rights of others.
The fact these people do not have the "right" to do so notwithstanding, it seems to me you actually have no problem with not only same-sex marriage, but incestuous marriage as well. Does that sound about right?
Ah, but allowing homosexual marriage does infringe upon my rights. Because then I have to pay taxes to the state for benefits to homosexual state-employees. I have to pay taxes to support a child welfare service that supports homosexual adoptions. And I also have to pay higher medical premiums when insurance companies are forced to recognize homosexual marriage.
And in a less concrete fashion, homosexual marriage brings with it a severe coarsening of the culture, and a hatred of many of the values that I hold dear.
I have debated this issue from your standpoint - from an entirely utilitarian, secular perspective that assumes the state exists as an entirely neutral entity with no moral value of its own, beyond a definition of "the rights of man." I'll be happy to give you another argument as to why homosexual marriage is a travesty, and a potential disaster to the health of nation.