The constitutional requirement, U.S.Const.Amend. V, of an indictment or presentment as a predicate to a prosecution for capital or infamous crimes has for its primary purpose the protection of the individual from jeopardy except on a finding of probable cause by a group of his fellow citizens, and is designed to afford a safeguard against oppressive actions of the prosecutor or a court. The constitutional provision is not to be read as conferring on or preserving to the grand jury, as such, any rights or prerogatives. The constitutional provision is, as has been said, for the benefit of the accused. The constitutional provision is not to be read as precluding, as essential to the validity of an indictment, the inclusion of requisites which did not exist at common law.
Traditionally, the Attorney for the United States had the power to enter a nolle prosequi of a criminal charge at any time after indictment and before trial, and this he could have done without the approval of the court or the consent of the accused. It may be doubted whether, before the adoption of the Federal Rules of Criminal Procedure, he had any authority to prevent the ...