But the leap from not defending DOMA to taking a position that same-sex couples have a constitutional right to marry is not very great. Indeed, it seems almost preordained by the conclusion that sexual orientation is a classification, like race or gender, subject to heightened scrutiny.

Once that tougher test for justifying a law is triggered, the chance of it being deemed constitutional plummets, and rightly so. Where fundamental rights are involved, where the groups being targeted have a history of being discriminated against, their freedom to marry should not depend on whether they live in Mississippi or Massachusetts. The president, as a former constitutional law professor and, even more, as the son of a couple whose marriage would have been illegal in 22 states, surely understands this point. States, like presidents, evolve. But in the end, the rights of gay Americans, as those of African Americans, cannot be left to majority whim.