Marriage is a three-party contract between a man and a woman (although some state laws use the term "persons capable of contracting" or similar language, that would exclude minors and incompetents, but not necessarily persons of the same sex) and the state, which acknowledges its consent to the marriage contract through the issuance of a license. Few persons realize that the state is a party to their marriage until they want to get divorced, which they consider a great inconvenience, not to mention the legal expense. However, the state has a legitimate, even compelling, interest in the incidents of the marriage, i.e., marital property rights, custody and care of minor children (whether born of the union or adopted), and obligations of support; which issues are subject to the jurisdiction of the several states based upon the parties? residence or domicile.
It should be noted that there is no express provision in the Constitution granting a person the right of marriage; not that the framers thought marriage unimportant, but rather it is a right retained by the people under the Ninth Amendment, and power reserved to the several states or to the people under the Tenth Amendment. Marriage is strictly a matter of state (not federal) law. Each state has the sovereign power to enact laws governing marriage; and provided that such laws do not infringe upon a citizen?s rights under the Fourteenth Amendment, they are valid and enforceable. See, e.g., Loving v. Virginia, 388 U.S. 1 (1967). It is the recent instances of states recognizing same-sex marriage that has prompted the move to amend the Constitution to provide a definition of marriage as between a man and a woman; which would be an intrusion on states? rights to govern marriage, and an unwarranted limitation on the liberty of the people.
The problem, perhaps, is the failure to differentiate between marriage as a religious rite, and its place as a secular institution of society. In this regard, efforts to legislate the morality of marriage will not add to its sanctity, and only detract from its social purpose by making a federal case out of it.