A proper understanding of the nature of the inherent powers begins with separating whether the judiciary has any constitutional power to overrule Congress from the judiciary’s power to act in the absence of congressional action, i.e. in the interstices of federal statutes and rules. Separating out these two very different types of powers helps clarify that the inherent powers of federal courts are actually both broader and shallower than have been previously thought: Congress has near plenary authority in this area, but the courts have a great deal of leeway to act when Congress has not. An examination of the history and text of the Constitution, the ratification debates, and the earliest cases establishes that it is Article I’s necessary and proper clause, not Article III’s “judicial power” or “courts,” which controls any inherent judicial authority. As such, Congress has near plenary authority over the structure and procedure of the federal courts. With the power of Congress in mind, however, the judiciary has substantial authority to act when Congress has not. The Framers created a remarkably flexible judicial branch based upon the way common law courts operated in the late-18th century. Those courts regularly acted in the absence of legislative authority in a multitude of ways, bound by the common law and current practice, but not by legislative silence. Thus, as long as a federal court’s use of the inherent power has not been foreclosed by an existing Act of Congress and is reflective of the judicial power – i.e. helpful to the deciding of cases – courts are empowered to act, as long as they understand that Congress can always fix what it does not like. This analysis also best explains what courts have done since the framing. While the Supreme Court has repeatedly claimed an inherent power strong enough to invalidate a congressional act in dicta, it has never actually invalidated one, even in situations where Congress has substantially impinged upon traditional areas of inherent power like rule making or contempt. This understanding of congressional and judicial power thus offers an elegant solution to the thorny problem of inherent powers and squares the circle by fitting a unified theory to the history, language and structure of the Constitution and the more modern, pro-judiciary case law.