In the Supreme Court’s opinion overturning Roe v. Wade, Justice Samuel Alito writes that “nothing in this opinion should be understood to cast doubt on precedents that do not concern abortion.”

Clarence Thomas, in his concurrence, suggests otherwise.

Thomas voted with the 6-3 majority that struck down Roe. In a concurring opinion, however, he expressed the view that he would go further — much further — than the majority in thinking through the implications of today’s decision. One passage in particular captured people’s attention:

In future cases, we should reconsider all of this Court’s substantive due process precedents, including Griswold, Lawrence, and Obergefell. Because any substantive due process decision is “demonstrably erroneous,” we have a duty to “correct the error” established in those precedents.

The key concept is the term “substantive due process,” which refers to the idea that the Constitution protects rights that are neither purely procedural (like rights to fair trial procedures) nor explicitly mentioned in the Constitution (like the freedom of the press). Thomas is arguing that such “unenumerated” rights are basically made up: not just the right to abortion protected in Roe, but also protections for birth control in Griswold v. Connecticut, same-sex sexual relations in Lawrence v. Texas, and same-sex marriage in Obergefell.

This does not mean that these rights are necessarily in danger now. In fact, such future rulings may well be unlikely. Thomas has a long history of unsuccessfully calling for the overruling of longstanding precedent, and Alito’s majority opinion goes out of its way again and again to emphasize that it would not have the implications Thomas wants. Together, these facts suggest that the other conservatives are wary of going down the road Thomas is paving, and that he would have few votes for enacting his extraordinarily radical vision.

But just because it’s unlikely doesn’t make the possibility any less chilling when spelled out in a Supreme Court concurrence. And Thomas’s concurrence exposes the incoherent logic at the heart of Alito’s ruling — and a fundamental problem with the way the Supreme Court operates.

How Thomas exposed the majority’s incoherence

The basic argument in Alito’s ruling in Dobbs v. Jackson Women’s Health is that there is no explicit constitutional protection for abortion rights, and that any right not explicitly enumerated in the Constitution must be “deeply rooted in this Nation’s history and tradition” and “implicit in the concept of ordered liberty” in order to qualify for constitutional protection. Abortion, he argues, does not pass this test.

But if abortion fails, it’s hard to see how rights to same-sex marriage and contraception pass. Though Thomas’s reasoning is far more extreme than the majority’s, his concurrence shows that it’s difficult to put a limiting principle on a ruling rolling back these legally interconnected rights. The Court can declare all it wants that this ruling only applies in one case, but it becomes harder to see why once you start following the logic.

It’s not just Thomas who sees that. It’s also an argument that the liberal minority — Justices Elena Kagan, Stephen Breyer, and Sonia Sotomayor — make in their joint dissent:

The lone rationale for what the majority does today is that the right to elect an abortion is not “deeply rooted in history”: Not until Roe, the majority argues, did people think abortion fell within the Constitution’s guarantee of liberty. The same could be said, though, of most of the rights the majority claims it is not tampering with. The majority could write just as long an opinion showing, for example, that until the mid-20th century, “there was no support in American law for a constitutional right to obtain [contraceptives].” So one of two things must be true. Either the majority does not really believe in its own reasoning. Or if it does, all rights that have no history stretching back to the mid-19th century are insecure. Either the mass of the majority’s opinion is hypocrisy, or additional constitutional rights are under threat. It is one or the other.

The majority’s response to this argument is that abortion is somehow a unique case: “rights regarding contraception and same-sex relationships are inherently different from the right to abortion because the latter (as we have stressed) uniquely involves what Roe and Casey termed ‘potential life.’” It’s worth noting that this reassurance was in the final opinion, but not in the version that was leaked in May.

But the fact that abortion raises questions about ending lives does not make it any more or less “deeply rooted in our history”: it’s an act of pure legal handwaving, an invention of a standard designed to escape the obvious consequences of his own logic.

Nor is there any clear reason in the Dobbs treatment of stare decisis, the principle that courts generally ought to adhere to precedent, that would prevent its logic from being applied to these other landmark constitutional cases. Some of the Court’s reasons that Roe was so egregiously bad that it deserved to be overturned — that it, for example, “usurped the power to address a question of profound moral and social importance that the Constitution unequivocally leaves for the people” — could also apply to Griswold or Obergefell.

Instead of setting up clear standards, it seems that Alito and his colleagues are trying to make the problem exposed by Thomas and the dissenters disappear: to assert that their logic doesn’t apply to what it obviously does.

As a practical matter, this might very well work: The Court majority is not bound by any formal rules other than the ones it decides on. It can simply do whatever it wants for whatever reason it wants; if it does not want to extend the logic of its own ruling to similar cases for arbitrary reasons, it can easily do that.

But this should reveal to the rest of us that what Alito and company are doing is not simply following legal principles wherever they lead: They are exercising power, reshaping the law according to their own political beliefs and calculations about potential political backlash.

Ironically, a ruling decrying the Court behaving like a legislature is engaged in much the same enterprise. And this, in turn, raises the question of whether nine unelected judges really should have the power we’ve given them.

Correction, 3 pm: A sentence previously included in this article referred to Clarence Thomas’s dissent instead of concurrence. He voted with the 6-3 majority to overturn Roe.