Same-sex marriage may be the new third rail in the culture wars: Touch it at your peril. Emotions, understandably, get worked up very quickly on all sides. It is difficult to tell someone who is in a long-term, committed same-sex relationship that you value their relationship differently from the way you value a heterosexual marriage. But, for us Catholics, getting the correct analogy matters.
In this instance, the correct analogy is not between a gay marriage and a straight one. It is between a same-sex union and other types of non-marital relationships. Human friendship takes many forms, and all of them can be a source of blessing. But, marriage is not like other forms of friendship, it stands alone within the Christian tradition for whom its bonds of love have themselves become an analogy for the relationship which exists between Christ and His Church. Those who wish to advocate for same-sex marriage within a Catholic context must cite theological, not legal or sociological, arguments and, so far, those arguments do not exist.
This notion of finding the correct analogy is important because it is not enough for us Catholics to oppose same-sex marriage. One of the consequences of legislation permitting civil unions or same-sex marriage is that more people have access to health care and other social benefits. The Church supports extending such benefits. So, if we merely say "No" on same-sex marriage we are, in effect, opposing our own teaching about the need to extend social benefits as widely as possible.
This is where the Levada solution comes in and the proper analogy makes sense. In this complex society of ours, there are all sorts of relationships other than marriage in which it would highly benefit those involved to receive social benefits like health care. It could be an unemployed cousin or friend, a retired parent, a same-sex partner, or, for that matter, a heterosexual couple who for whatever reasons choose not to get married. The Church has no problem if such "joint habitation" partnerships receive social benefits. This was first proposed in San Francisco by then-Archbishop William Levada, now the Cardinal-Prefect of the Congregation for the Doctrine of the Faith. It was followed recently in Puerto Rico when their legislature revised the civil code for that nation and has served as a model for other Latin American countries. It is an example of casuistry at its best.
If I may introduce yet another analogy, one of my problems with the response of some bishops to the Notre Dame controversy was that their statements, however well intended and designed to articulate the Church’s undying commitment to the dignity of the unborn, nonetheless could so easily be manipulated for partisan purposes. In the debate about same-sex unions, we need not apologize to anyone for our belief that marriage was ordained by God and that the way our current laws enshrine the marriage of one man and one woman is a cultural achievement of the first order. But, we Catholics also need to make sure that our statements are not serviceable for homophobic bigots.