This is not because the court deferred to the IRS, an independent agency, in interpreting the statute. On the contrary, the court denied the power of the IRS — and, inferentially, the power of the executive branch — to be the final word on statutory interpretation. Instead, the court, in the act of deference to Congress’s objective in enacting the ACA, asserted its power to render the final, if properly deferential, word in interpreting what Congress does. Thus did judicial aggression against one branch come cloaked in the cloth of deference to another.

Construing the Constitution in the Arizona case, Roberts said the Framers’ language was as clear as their purpose, to which deference is due. Interpreting the health-care statute, Roberts said Congress’s language was “inartful” but, read in the context of the ACA’s structure, was not ambiguous and should not defeat Congress’s purpose, to which the court owes deference.

Roberts’s ruling advanced a crucial conservative objective, that of clawing back power from the executive branch and independent agencies that increasingly operate essentially free from congressional control and generally obedient to presidents. If conservatives cannot achieve their objectives, including ACA repeal, through the legislative branch, conservatism’s future is too bleak to be much diminished by anything courts do. If, however, conservatives can advance their agenda through Congress, they will benefit from Roberts’s ACA opinion, which buttresses legislative supremacy.