[I]t seems to me at this time we need education in the obvious more than investigation of the obscure.
--Oliver Wendell Holmes, Jr.(1)
The definition, exclusive status, and legal benefits of marriage may become one of this decade's most important domestic policy issues in the United States. Many articulate and influential scholars, lawmakers, and commentators are asking why the preferred legal status and benefits of marriage should not be extended to unions other than traditional marriages (that is, exclusive, presumably lifelong, state approved consensual unions of a man and a not-closely-related woman).(2) Why should marriage be the only preferred and specially recognized connubial relationship in our laws while other forms of intimate personal relationships are denied the same or similar legal status? Why shouldn't same-sex marriage be legalized, or an equivalent marriage-like status be created (such as "civil union" or "domestic partnership") for same-sex couples?(3)
A. Can the Proposed Legalization of Same-Sex Marriage Be Justified in Terms of the Compelling Social Interests That Justify the Legalization of Traditional Marriage?
The movement to legalize same-sex marriage asks defenders of exclusive legal protection for heterosexual marriage to explain why our laws should permit heterosexual marriage but should not allow same-sex marriage or some marriage-like alternative status for same-sex couples. That question, however, gets the burden of proof backwards; the burden should rest on those who argue for a substantial change in the arrangement of a fundamental social institution to show justification for the proposed change.(4) Accordingly, a significant change in the definition or structure of a basic social institution like marriage should be considered seriously only if advocates of the proposed change first show by convincing evidence that the proposed change is likely to improve the institution of marriage or otherwise improve society. The burden is on advocates of same-sex marriage to show that legalizing same-sex marriage would comparably fulfill the public policies and social interests that underlie legal marriage, or fulfill other, equally compelling public policies and social interests. However, despite an outpouring of literature advocating same-sex marriage, the evidence that legalizing same-sex marriage or some equivalent domestic status would effect an overall improvement in the institution of marriage or in society is lacking.(5) Indeed, there are substantial indications that legalizing same-sex marriage would undermine some of the important social purposes for marriage and would ultimately harm society.
I have argued elsewhere that claims that the United States Constitution mandates legalization of same-sex marriage are unsupported by the text, history, or precedents interpreting the Constitution, or any viable interpretation of constitutional doctrine.(6) Of course, just because the Constitution does not mandate legalization of same-sex marriage does not end the discussion; lawmakers may adopt laws that are not constitutionally mandated if they are not constitutionally forbidden, and it has not yet been suggested that the U.S. Constitution forbids the legalization of same-sex marriage.(7) Moreover, constitutional claims for same-sex marriage may turn on an assessment of the comparative contribution of traditional heterosexual marriages and of same-sex unions to the social interests that underlie marriage laws, and how important those interests are to society.(8)
If the legalization of same-sex marriage were clearly shown to contribute to the social interests and policy purposes that underlie traditional marriage, then, of course, lawmakers could rationally choose to legalize same-sex marriage; but if not, that choice would be arbitrary and suspect. Moreover, if same-sex unions do not contribute to the essential social purposes of traditional marriage, a state that confers the legal status of marriage upon same-sex unions commits fraud when it presents a false image of same-sex unions as comparable to traditional marriage. …