Agencies and Legislative/Judicial Power

City of Arlington v. FCC has some interesting nuggets.  For instance, Scalia’s majority flatly states: “Make no mistake—the ultimate target here is Chevron itself,” though the dissent disclaims any such intent.  But I want to flag here another iteration of debates over how to characterize agencies’ power.  Roberts’ dissent says that

Although modern administrative agencies fit most comfortably within the Executive Branch, as a practical matter they exercise legislative power, by promulgating regulations with the force of law; executive power, by policing compliance with those regulations; and judicial power, by adjudicating enforcement actions and imposing sanctions on those found to have violated their rules.

Scalia’s majority opinion responds that

the dissent overstates when it claims that agencies exercise “legislative power” and “judicial power.” The former is vested exclusively in Congress, U. S. Const., Art. I, §1, the latter in the “one supreme Court” and “such inferior Courts as the Congress may from time to time ordain and establish,” Art. III, §1. Agencies make rules (“Private cattle may be grazed on public lands X, Y, and Z subject to certain conditions”) and conduct adjudications (“This rancher’s grazing permit is revoked for violation of the conditions”) and have done so since the beginning of the Republic. These activities take “legislative” and “judicial” forms, but they are exercises of—indeed, under our constitutional structure they must be exercises of—the “executive Power.” Art. II, §1, cl. 1.

Note that Roberts is saying that “as a practical matter” they exercise legislative and judicial power, and Scalia is saying that as a constitutional matter they don’t. But perhaps Roberts has come to the conclusion that, as a constitutional matter, agencies exercise these powers as well. Justice Stevens, after all, said as much in his concurrence in Whitman v. American Trucking Associations, Inc.