The Fifth Amendment specifically excepts from the indictment requirement those cases "arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger." Indeed, all offenses arising under the Uniform Code of Military Justice in which the accused is on active duty in the military service may be prosecuted by court-martial. Solorio v. United States, 483 U.S. 435 (1987).
Criminal contempt represents another exception to the rule that prosecutions must be initiated by an indictment or information. Proceedings under 18 U.S.C. § 401 may be initiated summarily by the court or upon notice and hearing in accordance with Rule 42, Fed. R. Crim. P. See Green v. United States, 356 U.S. 165 (1958); United States v. Armstrong, 781 F.2d 700, 703 (1985). An indictment, although not required, may be used. See United States v. Mensik, 440 F.2d 1232 (4th Cir. 1971). However, in the case of contempt of Congress under 2 U.S.C. § 194, the use of an indictment is required by statute and must be employed. See Russell v. United States, 369 U.S. 749 (1962).