Thomas Krannawitter, reacting to Willie Nelson's gay cowboy song writes:
Any argument that seeks to defend traditional marriage and the natural family must be...an argument. It must begin by defining certain principles and then draw logical and necessary conclusions from those principles. But can these arguments be persuasive, however tightly-reasoned they might be, if the American people no longer believe in moral principles?
Those who seek to redefine marriage are perhaps most successful in the court of public opinion when they avoid argumentation altogether. They need only hold up a photograph of two women or two men holding hands (they are probably shrewd enough not to present an image of three men, but that is a different though related problem), and then ask why these decent citizens ought not have the full privileges and rights of marriage enjoyed by all married heterosexual couples. This is no argument, but it can be quite successful in shaping opinion.
It's funny that Krannawitter accuses the pro-gay side of being most successful when they "avoid argumentation" because the historic case against homosexuality rests largely on such "non-argument" grounds. Let's see: There is an unquestioned appeal to religious texts or traditions, Leviticus, et al. -- that's not an argument. There is also the (previously) unquestioned tradition of morally stigmatizing homosexuality -- that's not an argument either. And certainly Krannawitter knows that not just the legal and moral prohibitions on interracial relations, but slavery itself was vetted by traditional morality.
Now, there is indeed an "argument" against homosexuality. And certainly Claremont has been prominently making that argument (hence to link to Harry V. Jaffa making it). But in examining Claremont's argument -- when they "defin[e] certain principles and then draw logical and necessary conclusions from those principles" -- we see that they've already lost the American public. Their argument rests on the premise that natural differences between the sexes demonstrate procreation as the teleology of the sex act. See Ed Feser's piece (and my reaction) for an articulate variation of Claremont's argument. When we "then draw logical and necessary conclusions from those principles" we see that not only is homosexuality "wrong" because it's "unnatural" but so to is, in Feser's words, "ejaculating into a Kleenex, or a condom, or into any bodily orifice other than a vagina." So there you go, a married Christian couple having contracepted sex, any heterosexual couple having oral sex, or any male teenager masturbating is as unnatural and "wrong" as homosexuality according to Krannawitter's argument.
Now, Claremont/Feser may be morally right (I don't think they are), but they've lost the American people with their argument long ago (I don't think I need to cite the stats on contraception, oral sex, and masturbation among the American public, do I?).
Also, there are some variations of the natural law argument that focus more on the man/women natural distinction than on procreation per se (Jaffa has attempted to leave himself such an "out" -- see this post of mine focusing on the failure of Jaffa's man/woman natural distinction argument). For instance, once I debated someone who claimed that oral sex and contraception could be viewed as natural under the aegis of the "pair-bond." But, in doing so, he (sneakily) attempted to shift the focus from "procreation" to "pair-bonding." And guess what, homosexuals can "pair-bond" just as effectively as heterosexuals. Thus, in making the natural law argument, all roads lead to procreation. This is why, in the comments section of Feser's post, reacting to Francis Beckwith's pondering the possibility that married contracepted sex is "natural," Right Reason site editor Max Goss asserts that such an argument "would justify sodomy" and therefore, could not be countenanced. Good for Goss and Feser for having the intellectual honestly to take their position and consistently defend it, even if it's been deemed a loser with the American public.