Endicott Johnson Corp. v. Perkins (317 U.S. 501 (1943)) was a follow up to Crowell v. Benson (285 U.S. 22 (1932)), and applied the notion of ultra vires to subpoena powers. In the case, Johnson resisted a subpoena because they felt that the Administrative Agency was acting outside their jurisdiction. The Court found that the information in the subpoena was necessary for the agency to determine where their jurisdictional limits were. Basically, an agency can conduct an inquiry to determine their jurisdiction, even if it later turns out that the people getting subpoenaed were outside of the agency's jurisdiction.