The reason the same-sex marriage debate is going to continue, regardless of the Supreme Court’s decisions, is that its central tension is hidden beneath the superficial issue.

On its face, same-sex marriage appears to be an equal-protection question, which is why the prima facie arguments in favor of it are so powerful. But the real issues are much deeper and involve a conflict between competing ideas about freedom.

To many parts of the left, same-sex marriage isn’t just about “equality.” It’s about a bunch of other things, too. It’s a first step on the road to radically redefining marriage to include polygamy (and generally “weakening” the institution altogether)—the overall goal being to “transform the notion of family entirely.” This isn’t scaremongering, by the way. As Ryan Anderson helpfully demonstrates, gay-marriage advocates explicitly advance these ideas. There’s even more here. So please, do them the courtesy of taking them at their word.

Yet one gets the sense that, at root, the same-sex marriage project isn’t even really about opposition to the family as it is currently conceived—no matter how outmoded and bourgeois it may be. No, the family is just necessary collateral damage in the real struggle for sexual liberation. I suspect that, to the left, arguments about contraceptives, abortion, and gay marriage are really all about the same thing: the idea that sexual behavior must not be discriminated against, by anyone, in any sense. There must be no adverse outcomes; there must be no distinctions made; and any form of disapproval is tantamount to discrimination. Other freedoms—of speech, of liberty, of thought—may be, to some extent, negotiable. But for the left, sexual freedom is a paramount freedom.