In Theard v. United States, 1956, the Supreme Court ruled that a state cannot disbar an attorney who has been suspended from practicing law in federal courts but not convicted of any crime. The case involved New Orleans lawyer Dominic J. Theard who was indefinitely suspended by a federal court for unprofessional conduct and subsequently disbarred by Louisiana without further proceedings on the grounds of his suspension alone. In its decision, the Supreme Court held that while states have broad power to establish standards for licensing professionals within their borders, they cannot automatically impose sanctions based solely on discipline imposed by a federal court as it would infringe upon separation of powers principles inherent in our Federal Constitution system.

In the dissenting opinion for Theard v. United States, Justice Frankfurter argued that the Supreme Court does not have exclusive authority to disbar attorneys from practicing before it. He contended that while the court has a right to protect itself from unfit practitioners, this power should be used sparingly and only in clear cases of misconduct which directly affect its proceedings. He believed that state courts are better equipped to handle disciplinary matters due to their closer proximity and familiarity with local legal communities. Furthermore, he expressed concern about potential conflicts between federal and state authorities over attorney discipline issues if both were allowed concurrent jurisdiction in such matters.