Ginsburg’s question presupposes an inaccurate (to put it mildly) narrative about the development of marriage law.
While many have celebrated the result in Obergefell v. Hodges, fewer have praised the craftsmanship of Justice Anthony Kennedy’s opinion. That is as it should be because the opinion is longer on sentiment and empathy than legal analysis. And yet it is now as much a part of the United States Reporter as the most well-reasoned judgment. Thus, it is worth looking at its doctrinal implications, none of which are happy.
First, Kennedy consciously removes the historical constraints on the Court’s ability to declare new fundamental rights. Washington v. Glucksberg (1997), the most important modern substantive due process case, required fundamental rights to be deeply rooted in the history and tradition of America. Whatever else can be said about it, same-sex marriage does not begin to meet that test. Kennedy says correctly that some other substantive due process cases did not meet that test either (Roe comes obviously to mind). While Kennedy does not quite say that he is overruling Glucksberg altogether, its relevance has been gravely weakened. Justices seem free to look to their views on the nature of justice rather than history to discern new fundamental rights.
While some libertarians in the past have been enthusiastic about this development, it is unlikely the Court will use this power to pursue economic liberties. I think this development is likelier to revive claims that some other social rights, like the right to assisted suicide, are also constitutional ones.
Kennedy also gestured to the equal protection clause in his decision. I say gestured because he did not conclude that homosexuals were a suspect class, discrimination against whom triggered strict scrutiny. But this very absence of analysis may encourage arguments that other groups are sufficiently like the classic racial and ethnic minorities, even if not suspect classes, that the classifications which disadvantage them should receive some kind of heightened scrutiny. Here I would think renewed litigation might target the decision in San Antonio Independent School District v. Rodriguez (1973) that rejected the proposition the poor could be a suspect class in the context of school financing.
Finally, the case is notable for arguing that state recognition of marriage is a liberty. Justice Clarence Thomas powerfully argues that it cannot be one, because the liberty that the Constitution protects is negative. It prohibits the government from interfering with individual rights but does not require the conferral of government benefits. This line is the one that so far has made it impossible to seriously argue even under an adventurous view of substantive due process that the Constitution confers welfare rights. Look for the Left to argue that Obergefell begins to erase it.
Now I want to be clear, I do not believe we will see welfare rights, the poor as a suspect class, or even the right to assisted suicide this year or next. Justice Kennedy at least would not be enthusiastic about most of them. But say Hillary Clinton gets a few appointments. The ground has been laid for a progressive substantive due process clause and a less disciplined equal protection clause. Kennedy’s opinion disclaims “caution” and its doctrinal development, such as it, is very incautious.