As Prop 8 proponents argue, Judge Walker’s ruling is contrary to the governing Supreme Court precedent of Baker v. Nelson (1972), which Walker’s ruling doesn’t even mention:

In Baker v. Nelson, 409 U.S. 810 (1972), the Supreme Court unanimously dismissed, “for want of [a] substantial federal question,” an appeal from the Minnesota Supreme Court presenting the same questions at issue here: whether a State’s refusal to authorize same-sex marriage violated the Due Process and Equal Protection Clauses of the Fourteenth Amendment. The same-sex couple in Baker placed primary reliance on Loving v. Virginia, 388 U.S. 1 (1967), which had been decided five years earlier. The Baker Court’s dismissal was a decision on the merits that is binding on lower courts on the issues presented and necessarily decided, Mandel v. Bradley, 432 U.S. 173, 176 (1977) (per curiam), and its precedential value “extends beyond the facts of the particular case to all similar cases,” Wright v. Lane County Dist. Court, 647 F.2d 940, 941 (9th Cir. 1981). Plaintiffs’ claims are the same as those rejected in Baker, and the district court’s decision thus conflicts with a binding Supreme Court authority.

The point here is not that the Supreme Court must give full precedential weight to Baker v. Nelson.  Nor does Prop 8 proponents’ argument rest on any prediction about what the Court will do if and when it revisits the questions that it dismissed in Baker.  Rather, the point is that, unless and until the Supreme Court revisits the questions, the lower federal courts are obligated to give Baker precedential value.

This is a point on which I would think all nine justices would agree.  Any other approach would invite all sorts of mischief by lower-court judges.

To be sure, there will be times when intervening Supreme Court cases make clear that previous rulings no longer stand.  But that’s certainly not the case on same-sex marriage, as Justice Kennedy’s majority opinion in Lawrence v. Texas expressly stated that that case did “not involve whether the government must give formal recognition to any relationship that homosexual persons seek to enter.”  One can argue, as Justice Scalia did in dissent in Lawrence, that the majority’s approach in that case, if extended to marriage, would lead to invention of a federal constitutional right to same-sex marriage.  But it’s a very different matter for a lower-court judge to regard Lawrence as a license to ignore Baker (which evidently is what Walker did).