Last month, when Justice Anthony Kennedy found that same-sex marriage was a “fundamental right,” did he and the four other justices for whom he wrote find a “new” constitutional right? Or is it rather, as some of us have long argued, that the Constitution protected that right for nearly a century and a half, like the right to same-sex sodomy (Lawrence v. Texas), to sell and use contraceptives (Griswold v. Connecticut), to educate one’s child in a parochial school (Pierce v. Society of Sisters), and, dare I say, to freedom of contract in employment (Lochner v. New York)?

I address those questions in a piece in today’s National Law Journal, defending Kennedy’s conclusion in Obergefell v. Hodges but taking exception to his reasoning. The fundamental right to same-sex marriage rests mainly, he argued, on the liberty interest that is protected under the Fourteenth Amendment’s Due Process Clause. Not so, said Justice Clarence Thomas in his dissent. Drawing extensively on John Locke’s state-of-nature approach to political legitimacy, which the Founders and Framers drew on as well, Thomas argued that the Obergefell plaintiffs were not denied the right to marry. They were perfectly free to go to any willing clergyman who would marry them—and the state would not have interfered with their liberty to do so. What they wanted, he saw, was a state license, the state’s positive recognition of the marriage, and the legal benefits that go with the state’s recognition.

Kennedy’s conclusion as against the state, therefore, belongs properly not under the Fourteenth Amendment’s Due Process but under its Equal Protection Clause. The state denied same-sex couples the same benefits it granted opposite-sex couples and thus discriminated against them. Thus, the right to marry someone of the same sex may be a natural right that anyone would enjoy in the state of nature; but once we leave that state, if an actual state we’re in grants the privileges of marriage, the denial of those privileges is properly litigated against the state under the Equal Protection Clause. Unfortunately, Thomas never developed those points—nor could he have without coming out for same-sex marriage—nor did Kennedy’s brief and gauzy discussion of equal protection get to the heart of the matter either.

But to return to the questions with which I began above, the most disquieting aspect of the five opinions the case generated—the four dissenters wrote separate opinions—was found in Chief Justice John Roberts’ dissent. Focusing on Kennedy’s mistaken Due Process argument, Roberts took the occasion to launch a sustained attack against the Court’s discovery of unenumerated rights under the Due Process Clause. However off-point in Obergefell, his attack—citing the “discredited” Lochner decision no fewer than 16 times—included such Holmesian-like gems as “the Fourteenth Amendment does not enact John Stuart Mill’s On Liberty.”

Only Kennedy, for all his fuzziness, came close to putting his finger on the core of the matter before us—the constitutional status of the unenumerated rights at issue in cases like those mentioned above. The Obergefell plaintiffs, he wrote, almost in passing, “pose no risk of harm to themselves or third parties.” Indeed! That could have come straight out of John Stuart Mill. But the source is irrelevant. Rather, the constitutional point is that if the state is going to restrict your liberty, it has to have a very good reason—that’s what the Constitution, at bottom, is all about. And from Lawrence all the way back to Lochner, the state didn’t have a good reason for limiting the liberty of the plaintiffs, which means that their right was always there to be protected, even though, as in Lawrence, the Court hadn’t recognized it when it ruled otherwise, 17 years earlier in Bowers v. Hardwick, the case Lawrence overturned.

In Obergefell, Kennedy seemed to notice that when he wrote, quoting his opinion in Lawrence, that Bowers was “not correct when it was decided.” It would have been good if he had then drawn expressly the implicit conclusion, that the right at issue was always protected. It didn’t take “new insights and societal understandings” to discover that, as he averred in Obergefell. It takes simply a plain understanding of the theory of our Constitution of liberty.