Finally, there is the question of civil unions. Some politicians and others say that they are against same-sex marriage but in favor of legal recognition of same-sex partnerships, with all or most of the rights and responsibilities of marriage, only falling under a different rubric. If law and policy are at least to do no harm to marriage, it is critical that they avoid treating nonmarital conduct and relationships as if they were marital. There are clear moral lines—and not merely semantic ones—between what is marital and what is not, and the law should respect them. If they are blurred or erased, the public understanding of the meaning of marriage will erode.
Some of the benefits traditionally associated with marriage may legitimately be made more widely available in an effort to meet the needs of people who are financially interdependent with a person or persons to whom they are not married. Private contracts between such people should be sufficient to accomplish all or most of what they consider desirable.
If, however, a jurisdiction moves in the direction of creating a formalized system of domestic partnerships, it is morally crucial that the privileges, immunities, and other benefits and responsibilities contained in the package offered to nonmarried partners not be predicated on the existence or presumption of a sexual relationship between them. Benefits should be made available to, for example, a grandparent and adult grandchild who are living together and caring for each other. The needs that domestic-partnership schemes seek to address have nothing to do with whether the partners share a bed and what they do in it. The law should simply take no cognizance of the question of a sexual relationship. It should not, that is, treat a nonmarital sexual relationship as a public good.
(Robert P. George, "Law and Moral Purpose," First Things [January 2008] [italics in original])
Keith Burgess-Jackson, J.D., Ph.D. 