When the Supreme Court decided Lawrence v. Texas in 2003, the majority opinion included language disavowing implications for same-sex marriage. In invalidating the Texas law forbidding "homosexual sodomy," Justice Kennedy wrote for the Court, the majority did not say that the government was obligated to grant official recognition to same-sex relationships (through marriage or otherwise). In dissent, Justice Scalia objected that, notwithstanding the Court's disclaimer, the logic of the case implied that there is a right to same-sex marriage.
Subsequent events largely proved Justice Scalia right. Before the end of the year, the Massachusetts Supreme Judicial Court ruled in the Goodridge case that the state's constitution guaranteed a right to same-sex marriage. Although the opinion did not cite Justice Scalia's Lawrence dissent, in repeatedly citing the Lawrence majority, the Massachusetts SJC made clear that it agreed with his logic.
Did Justice Scalia learn his lesson? Hardly. Earlier this year, when the Court invalidated Section 3 of the Defense of Marriage Act in United States v. Windsor, CJ Roberts wrote a dissent in which he argued that the majority's holding not only did not entail the invalidation of state laws banning same-sex marriage, but that it strongly pointed in the opposite direction, insofar as it relied on principles of federalism. But whereas Roberts was engaged in damage control, Scalia did not hold back. He let loose with the following:
the view that this Court will take of state prohibition of same-sex marriage is indicated beyond mistaking by today’s opinion. As I have said, the real rationale of today’s opinion . . . is that DOMA is motivated by “bare . . . desire to harm” couples in same-sex marriages. How easy it is, indeed how inevitable, to reach the same conclusion with regard to state laws denying same-sex couples marital status.Yesterday Justice Scalia's chickens came home to roost, at least in Utah. In a thoughtful 53-page opinion in Kitchen v. Herbert, federal District Judge Robert Shelby invalidated Utah's state constitutional amendment banning same-sex marriage. In support of his view that the 14th Amendment is best read to protect a right to SSM, Judge Shelby twice invoked Justice Scalia. First, he said that he "agrees with Justice Scalia’s interpretation of Windsor and finds that the important federalism concerns at issue here are nevertheless insufficient to save a state-law prohibition that denies the Plaintiffs their rights to due process and equal protection under the law." Later in the opinion, Judge Shelby approvingly quoted the portion of Justice Scalia's Lawrence dissent in which he said that Lawrence entailed a right to SSM because, as Judge Shelby noted, it "removed the only ground—moral disapproval—on which the State could have at one time relied to distinguish the rights of gay and lesbian individuals from the rights of heterosexual individuals."
Justice Scalia must have seen this coming. So why didn't he join CJ Roberts in the latter's dissent that attempted to limit the damage (from their perspective) in Windsor and why didn't he write something to similar effect in Lawrence? Let me offer three possibilities.
First, it's possible that Justice Scalia acted out of principle. Sure, it might be expedient to characterize the majority opinions in Lawrence and Windsor as leaving laws banning SSM untouched, but, in this view, Justice Scalia is a man of deep principle. It would be dishonest for him to say anything other than what he thinks--which is that the Court's opinions in these cases imply a right to SSM. If that means that there will be a right to SSM sooner (a result Justice Scalia thinks wrong as a matter of law), then so be it.
Second, it's possible that Justice Scalia would have joined the Roberts dissent or written one like it in Lawrence if he thought it would do any good, but he is enough of a legal realist to understand that whether and when we get a constitutional right to SSM will not in any way depend on how he words his dissents. Accordingly, he may as well be honest (per "First", above).
Third, maybe he just can't stop himself. Perhaps Justice Scalia thinks (contra "Second"), that language in a dissent has at least a marginal impact on subsequent legal developments. But these gay-themed cases just get him so mad that he can't think or act strategically, and so he lets loose.
These possibilities are not mutually exclusive. I leave for readers to assign relative weights to the foregoing and/or other factors.