I was waiting for something like this in Windsor, which was joined by the Chief and Thomas. You can hear the relish in his voice.

It may be argued that if what we say is true some Presidential determinations that statutes are unconstitutional will not be subject to our review. That is as it should be, when both the President and the plaintiff agree that the statute is unconstitutional. Where the Executive is en- forcing an unconstitutional law, suit will of course lie; but if, in that suit, the Executive admits the unconstitution- ality of the law, the litigation should end in an order or a consent decree enjoining enforcement. This suit saw the light of day only because the President enforced the Act (and thus gave Windsor standing to sue) even though he believed it unconstitutional. He could have equally chosen (more appropriately, some would say) neither to enforce nor to defend the statute he believed to be unconstitu- tional, see Presidential Authority to Decline to Execute Un- constitutional Statutes, 18 Op. Off. Legal Counsel 199 (Nov. 2, 1994)—in which event Windsor would not have been injured, the District Court could not have refereed this friendly scrimmage, and the Executive’s determination of unconstitutionality would have escaped this Court’s desire to blurt out its view of the law.

This is the OLC opinion cited during oral arguments.

The matter would have been left, as so many matters ought to be left, to a tug of war between the President and the Congress, which has innumerable means (up to and including impeachment) of compelling the President to enforce the laws it has written. Or the President could have evaded presentation of the constitutional issue to this Court simply by declining to appeal the District Court and Court of Appeals dispositions he agreed with. Be sure of this much: If a President wants to insulate his judgment of unconstitutionality from our review, he can. What the views urged in this dissent produce is not insulation from judicial review but insulation from Executive contrivance.

Kennedy replies that it would be wrong to insulate the President’s decision from judicial review, if he fails to defend the law.

Kennedy made a similar point in his Perry dissent:

The California Supreme Court has determined that this purpose is undermined if the very officials the initiative process seeks to circumvent are the only parties who can defend an enacted initiative when it is challenged in a legal proceeding . . . . Giving the Governor and attorney general this de facto veto will erode one of the cornerstones of the State’s governmental structure. See 52 Cal. 4th, at 1126–1128, 265 P. 3d, at 1006– 1007. And in light of the frequency with which initiatives’ opponents resort to litigation, the impact of that veto could be substantial. . . . As a consequence, California finds it necessary to vest the re- sponsibility and right to defend a voter-approved initiative in the initiative’s proponents when the State Executive declines to do so