Let's begin with the official Church position on marriage. The Catechism defines is as follows:
"The matrimonial covenant, by which a man and a woman establish between themselves a partnership of the whole of life, is by is nature ordered toward the good of the spouses and the procreation and education of offspring; this covenant between baptized persons has been raised by Christ the Lord to the dignity of a sacrament."The CDF says the following:
"Marriage is not just any relationship between human beings. It was established by the Creator with its own nature, essential properties and purpose. No ideology can erase from the human spirit the certainty that marriage exists solely between a man and a woman, who by mutual personal gift, proper and exclusive to themselves, tend toward the communion of their persons. In this way, they mutually perfect each other, in order to cooperate with God in the procreation and upbringing of new human lives."This core Church teaching on the nature of marriage is part of the deposit of revelation and hence will never change. A starting point for all debate in this area must be to affirm this basic truth. It is certainly a high standard. But does this necessary imply that the Church must always oppose unions that do not approach such a standard? This is murkier territory. And for homosexual unions at least, the CDF answers in the affirmative. But it is not so simple.
The document begins by noting that homosexual unions are in no way similar to, and cannot even remotely approximate, the Catholic definition of sacramental marriage. Recognizing that the civil law is more limited than the moral law, it nonetheless maintains that laws in favor of homosexual unions are contrary to right reason and should be opposed. Should the state promote homosexual marriage, therefore, it would fail in its duty "to promote and defend marriage as an institution essential to the common good." The document notes carefully the difference between the public and private sphere, arguing that legal recognition of homosexual marriage would bring about "changes to the entire organization of society, contrary to the common good." The public authorities need to safeguard public morality, and especially to "avoid exposing young people to erroneous ideas about sexuality and marriage." This is the argument, in a nutshell.
In a very different context, John Courtney Murray came up with a very different answer. The issue was contraception. Back in the 1960s, Cardinal Cushing of Boston asked Murray for advice on how the Church should respond to the legalization of artificial contraception (for a more detailed discussion of the endurance of Murray's thought, see excellent essays by Susan Stabile and Gregory Kalscheur, S.J.) Murray argued that the Church should not oppose the decriminalization of contraceptive devices, not because he believed contraception was not immoral. Rather, he argued from the same principles that inspired Dignitatis Humanae. His key point centered on the distinction between law and morality, and, more specifically, the difference between public and private morality. Following Aquinas, he noted that the purpose of law is not to enforce what is morally right and oppose what is morally wrong (some religious traditions do not make this distinction-- think of Saudi Arabia).
It follows that people should be granted as much freedom as possible, and that freedom should only be restricted when absolutely necessary. The coercive function of law should only come into play in narrow circumstances, and should focus exclusively on safeguarding "public peace, public morality, and justice". But what does "public morality" mean? The key is preserving the common good. Murray himself referred to commonly accepted moral standards, by which he meant far more than mere majority opinion. Rather, he was thinking of truths that sprung from the natural law itself. But not all matters of public morality are fitting subjects for the law, he argued, as people can only be coerced into obeying minimal standards. In that sense, coercive law should restrict itself serious cases, addressing threats that "seriously undermine the foundations of society or gravely threaten the moral life of the community". Matters of enforcement call for prudence. And the law should certainly never address mere private morality.
In the context of contraception, Murray argued that it was firmly in the domain of private morality. While it may have public consequences, these would be difficult to control by law, and anyway, using coercive law might backfire and cause other social ills. Murray also invoked the principle of religious freedom. He noted in particular that it would be difficult for Catholics to oppose it when many religious leaders saw it as morally right. Case closed.
Some have attempted to make the same arguments for abortion that Murray made for contraception. This does not quite work, as abortion is clearly a matter of public, not private morality. Indeed, Pope John Paul II dealt with this very subject in his encyclical Evangelium Vitae. The late pope follows Murray in noting that civil law is more restrictive than morality, and that the law should concern itself only with "ensuring the common good of people through the recognition and defence of their fundamental rights, and the promotion of peace and of public morality" (in this, he references Dignitatis Humanae). John Paul goes on to argue that the law must recognize and guarantee the "fundamental rights which innately belong to the person", chiefly, "the inviolable right to life of every innocent human being". Thus abortion (and euthanasia), by attacking the right to life, are in a completely different category, and toleration cannot be defended based on Murray's arguments.
But what about legal recognition of homosexual unions? Is the Murray argument valid in this case. I believe it may well be. Homosexual behavior is clearly a matter of private, rather than public morality. Legal recognition of homosexual unions does not rise to the standard defined by John Paul in Evangelium Vitae, as it clearly does not threaten a fundamental right. In this vein, conservative writer George Weigel noted clearly that contraception is a matter of "conjugal morality and the sixth commandment" while abortion is a matter of "public justice and the fifth commandment". But using this taxonomy, homosexuality is also dealt with in the Catechism under the auspices of chastity and the sixth commandment. It tilts towards the contraception, not the abortion, camp.
However, the CDF document is more nuanced. Since the recognition of homosexual unions would change the definition of marriage, an institution essential to the common good, it could be considered public morality (the document does not address this public-private distinction explicitly). But, delving deeper, the comparison with contraception still holds.
In the first instance, although relating to private behavior, the legalization of contraception had implications for public morality, implications that some would call grave. It directly fostered more liberal attitudes to sex, and led to an enormous change in outlook. The CDF worries about homosexual unions encouraging "erroneous ideas" about sexuality and marriage-- the exact same charge can be leveled against artificial contraception. Even worse, the change in attitudes had an impact on abortion. It is by now a well-established argument that the legalization of contraception was the first step in a chain that led directly to legalized abortion. So, in a sense, the effects on public morality from legalized contraception were far worse than would be the case from recognizing homosexual unions. And yet Murray's argument still holds sway.
And what about marriage itself? As noted above, the Catholic approach to marriage, the sacramental approach, is a serous one. The vast majority of secular marriages probably would not pass muster with the Church. More and more, people do not see marriage as a lifelong commitment. Divorce is rampant, as serial monogamy becomes almost the norm. And yet the Church does not oppose legal divorce, while refusing to acknowledge its validity. This is a classic Murray position. The precarious state of civil marriage goes far beyond easy access to divorce. In many places, extended cohabitation has effectively replaced marriage as an institution. And the institution itself is often belittled. To take an extreme case, think of Britney Spears's alcohol-induced 48-hour Las Vegas marriage. A joke, right? And yet this marriage came with all the legal rights and responsibilities of every marriage. So, given the current state of the civil institution, it is hard to see how legal recognition of homosexual unions could do any more damage. To put it bluntly, if one is concerned about the "foundations of society" being undermined by what is happening to marriage-- they already are!
Even if the legal recognition of homosexual unions has consequences for public morality, there is a case, again appealing to the thought of Murray, for adopting a minimalist approach. Remember, Murray maintained that coercive law should be restricted to "relatively minimal standards of public morality" which would be affected by prudential calculations. In this light, a key question would be whether continued resistance to homosexual unions would be effective. Would it lead to even less respect for the institution of marriage? It is highly likely that a strategy of withholding any form of legal recognition would backfire in such a manner. Remember, the younger generation is the generation most likely to favor homosexual rights. Even though morality is not gauged by the will of the majority, the impact of this very real and growing "commonly accepted moral standard" will inevitably hamper any efforts to deny legal rights for homosexual unions. And remember, there is no fundamental right under attack (as would be the case with abortion) that would preclude acceptance of a civil law that the Church deemed not in full accord with the moral law.
So where do we end up? Let's hark back to Murray. He always started from the position that the role of law should be strictly limited, especially in the context of guiding moral action. So, as Gregory Kalscheur notes, "if society wishes to elevate and maintain moral standards above this minimal level of social necessity, it must look to institutions other than the law." Murray believed staunchly in the role of subsidiary mediating institutions, including the Church. There is a key lesson here. For as the Church continues to draw a hard line against tolerating secular homosexual unions, it is neglecting its own teaching role in the domain of marriage. By emphasizing the negative effects of a changes in the secular domain, it is blurring the clear distinction between the sacrament and civil marriage. It is even possible to argue that making peace with homosexual unions (at least civil unions that do not call themselves "marriage") provides the Church with the breathing space to draw a firmer line between what it sees as authentic marriage, and the very different secular norm. It would be free to point out the deficiencies of heterosexual marriages too. And, as secular and Catholic marriage diverge, the Church would be in a better position to restrict Catholic marriage to those who willing embrace its sacramental elements, and reject those who simply desire a Church wedding for good photos. And this would be a positive side effect...