Here is a snippet of the amicus brief of the U.S. Conference of Catholic Bishops.
California’s Proposition 8 encourages and supports the union of one man and one woman, as distinct from other interpersonal relationships, by giving it alone the name “marriage.” This is rationally related to legitimate state interests for several reasons.
First, as a matter of simple biology, the union of one man and one woman is the only union capable of creating new life. Second, the People of California could reasonably conclude that a home with a mother and a father is the optimal environment for raising children, an ideal that Proposition 8 encourages and promotes. Given both the unique capacity for reproduction and unique value of homes with a mother and father, it is reasonable for a State to treat the union of one man and one woman as having a public value that is absent from other intimate interpersonal relationships.
While this Court has held that laws forbidding private, consensual, homosexual conduct between adults lack a rational basis, it does not follow that the government has a constitutional duty to encourage or endorse such conduct. Thus, governments may legitimately decide to further the interests of opposite-sex unions only. Similarly, minimum standards of rationality under the Constitution do not require adopting the lower court’s incoherent definition of “marriage” as merely a “committed lifelong relationship,” which is wildly over-inclusive, empties the term of its meaning, and leads to absurd results.
The lower court’s definition of “marriage” also fails to reflect the deference to legislative decision-making that characterizes rational basis analysis generally. This is particularly egregious in a context where deference to States is especially warranted, both because marriage is a traditional concern of the States, and because ongoing controversies about marriage are currently working their way through reasonable democratic processes, yielding a range of results.The combined force of these objectives argues for upholding Proposition 8, even if this Court were to apply a higher level of scrutiny. Marriage, understood as the union of one man and one woman, is not an historical relic, but a vital and foundational institution of civil society today. The government interests in continuing to encourage and support it are not merely legitimate, but compelling. No other institution joins together persons with the natural ability to have children, to assure that those children are properly cared for. No other institution ensures that children will at least have the opportunity of being raised by their mother and father together. Societal ills that flow from the dissolution of marriage and family would not be addressed—indeed, they would only be aggravated—were the government to fail to reinforce the union of one man and one woman with the unique encouragement and support it deserves.
Proposition 8 is not rendered invalid because some of its supporters were informed by religious or moral considerations. Many, if not most, of the significant social and political movements in our Nation’s history were based on precisely such considerations. Moreover, the argument to redefine marriage to include the union of persons of the same sex is similarly based on a combination of religious and moral considerations (albeit ones that are, in our view, flawed). As is well established in this Court’s precedent, the coincidence of law and morality, or law and religious teaching, does not detract from the rationality of a law.
Finally, redefining marriage—particularly as a matter of constitutional law, rather than legislative process—not only threatens principles of federalism and separation of powers, but would have a widespread adverse impact on other constitutional rights, such as the freedoms of religion, conscience, speech, and association. Affirmance of the judgment below would create an engine of conflict in this area, embroiling this Court and lower courts in a series of otherwise avoidable disputes—pitting constitutional right squarely against constitutional right—for years to come.
Go here for a shorter synopsis about the USCCB filings of Supreme Court briefs supporting DOMA, and Proposition 8.
For more background, basic analysis, and links to all the amicus briefs (either pro or con), head on over to SCOTUS Blog.