I can recommend, sort of, that you read National Review’s recent cover editorial, “What Marriage Is For” (online, “The Case for Marriage“). It’s a good example of how not to make a case.
The article is a mass of non sequiturs. It assumes that if marriage is “for” something—regulating procreative sex—then using it for anything else must be “against” marriage, which is like saying that if mouths are “for” eating, we mustn’t use them for talking or breathing. It claims (conjecturally) that marriage would not have arisen if not for the fact that men and women make babies, from which it concludes that society has no stake in childless marriages.
It argues that marriage, and a culture of marriage, are good and important, a point on which thoughtful gay-marriage advocates enthusiastically agree. But, of course, our whole argument is that including gays won’t stop marriage from doing the good things it now does, and will probably strengthen marriage and the marriage culture. Maybe we’re wrong. But the editorial doesn’t even bother to engage. It proceeds as if “gay marriage is bad” follows obviously from “straight marriage is good.”
Confronted with the obvious fact that no society has ever excluded sterile heterosexual couples from marriage, and that excluding them would be absurd, the editorial simply baffles. “An infertile couple can mate even if it cannot procreate.” It can mate? If “mate” means “have heterosexual intercourse,” the argument merely assumes the conclusion, and “procreativity” has gone right out the window. The article notes that the inclusion of sterile straight couples does not prove that marriage “has nothing to do with” procreation. Right! But it also does not prove that marriage has only to do with procreation. In fact, it quite strongly suggests the contrary.
I could go on. The public, thank goodness, is thinking more seriously and clearly about marriage than are the editors of National Review, which is why the public is coming around.