As we saw in the preceding chapter, one can sensibly conclude that a law (or other policy) violates a constitutionally entrenched human right without also concluding that the Supreme Court should so rule. However, one cannot sensibly conclude that the Supreme Court should rule that a law violates a constitutionally entrenched human right without also concluding that the law violates the right; indeed, from a Thayerian perspective, the Supreme Court should rule that a law violates a constitutionally entrenched human right only if the Court concludes that the claim that the law does not violate the right is unreasonable. In this chapter, I argue that even a Supreme Court committed to Thayerian deference should rule that state refusals to extend the benefit of law to same-sex unions are unconstitutional – because the claim that such refusals are not unconstitutional is not merely mistaken but unreasonable.

Of course, it would be unrealistic (to put it mildly) to expect that any time soon the Supreme Court will rule that state refusals to extend the benefit of law to same-sex unions are unconstitutional. But that doesn't mean that such refusals aren't unconstitutional. In 1896, when Plessy v. Ferguson was decided, it would have been unrealistic to expect the Supreme Court to rule that de jure racial segregation violated the Fourteenth Amendment. Nonetheless, Justice Harlan was right, in his passionate and prophetic dissent in Plessy, that such segregation did violate the Fourteenth Amendment.