A right to use contraception is a right to use it without penalty by the government. Likewise, a right to abortion is a right to an abortion without undue government interference. So too, the right of adults to consensual sexual relations regardless of the sex of their partners protects against government regulation of such relations. By contrast, the right to marry asks the government to do more than stay out of the way.

Dissenting in Obergefell, Justice Thomas made just that point. By failing to recognize marriage, he said, states were not restricting anyone’s ability “to enter same-sex relationships, to engage in intimate behavior, to make vows to their partners in public ceremonies, to engage in religious wedding ceremonies, to hold themselves out as married, or to raise children.” Justice Thomas protested that “receiving governmental recognition and benefits has nothing to do with any understanding of ‘liberty’ that the Framers would have recognized.”

Justice Thomas was wrong about the bottom line in Obergefell, because he failed to take seriously the equal protection argument for same-sex marriage in states that recognize opposite-sex marriage. But he had a fair point about liberty, did he not? And if so, does that mean that a state really could abolish marriage for everyone?