By “long-standing practice,” Congress and the executive branch give principal-officer status to all “important and powerful” officials, even those who have a boss who can fire them. In 1976, the Supreme Court invalidated the law that created the Federal Election Commission to be composed of two members nominated by the president, two by the speaker of the House, and two by the president pro tempore of the Senate. The court held that all six must be nominated by the president as principal officers. Mueller, says Calabresi, is much more important and powerful than an FEC member. Congress has stipulated that the 93 U.S. attorneys are principal officers, and Mueller has, Calabresi says, “acted and has behaved like,” and is “much more powerful than,” any U.S. attorney. Compare, for example, Mueller’s job relative to that of the U.S. attorney for Wyoming. Mueller has “nationwide jurisdiction” and powers (e.g., to indict foreign citizens and corporations “without clearance from [the Justice Department]”) that have had “a major effect on” U.S. foreign policy, powers that “in effect and in practice” are “akin to” those exercised by an assistant attorney general, a principal officer. Mueller has been “without any real supervision” by Rosenstein, “who has treated Mueller as if he was ‘independent.’”

Furthermore, Calabresi says Mueller cannot be an inferior officer because “Congress has not, by law vested in the attorney general, the power to appoint special counsels to investigate wrongdoing” by high officials. The appointments clause creates a “default rule” that all U.S. officers are principal officers and it takes an “affirmative action” — a statute — to empower the attorney general to appoint a special counsel as an inferior officer, which Congress has not passed. The 1978 law that vested in a special court the power to appoint independent counsels expired in 1999.