Criminal procedure is the body of state and federal constitutional provisions, statutes, court rules, and other laws governing the administration of justice in criminal cases. The term encompasses procedures that the government must follow during the entire course of a criminal case, ranging from the initial investigation of an individual suspected of criminal activity, through arrest, arraignment, plea negotiations, pre-trial hearings, trial, post-trial motions, pre-sentence interviews, sentencing, appeals, and probation and parole proceedings. The rules of criminal procedure may also apply after a defendant has been unconditionally released following an acquittal. For example, the Double Jeopardy Clause of the Fifth Amendment to the U. S. Constitution may be invoked by individuals who are facing prosecution on charges for which they have already been found not guilty.
Criminal procedures are designed to safeguard both the innocent and the guilty from indiscriminate application of substantive criminal laws (i.e., laws prohibiting rape, murder, arson, and theft, etc.) and from arbitrary or abusive treatment at the hands of law enforcement, the courts, or other members of the justice system. At the federal level these safeguards are primarily set forth in three places: the Federal Rules of Criminal Procedure, Title 18 of the United States Code sections 3001 et seq., and Amendments IV, V, VI, and VIII to the U. S. Constitution. The rules and statutes reference each other, and both are designed to enforce and delineate in greater detail the rights established by the federal Constitution.
The Fourth Amendment prohibits the government from conducting unreasonable searches and seizures while investigating criminal activity and building a case against a particular suspect. The Fifth Amendment prohibits the government from compelling individuals to incriminate themselves, from denying individuals due process of law, from subjecting individuals to multiple punishments or prosecutions for a single offense, and from being prosecuted in federal court without first being indicted by a grand jury. The Sixth Amendment guarantees defendants the right to a speedy and public trial by an impartial jury, the right to be informed of all charges against them, the right to confront adverse witnesses, the right to subpoena favorable witnesses, and the right to an attorney. The Eighth Amendment prohibits the government from requiring excessive bail to be posted for pre-trial release, from imposing excessive fines, and from inflicting cruel and unusual punishments.
The freedoms safeguarded by the Fourth, Fifth, Sixth, and Eighth Amendments have two lives, one static and the other organic. Their static life exists in the original language of the amendments as they were ratified by the states in 1791, while their organic life exists in the growing body of state and federal case law interpreting their text, applying it, and defining its scope as different factual situations come before the courts. All of the rights protected by these four amendments, except the right to indictment by a grand jury, have been made applicable to state criminal proceedings via the doctrine of incorporation. Under this doctrine U. S. Supreme Court has said that no state may deny any citizen a fundamental liberty without violating the Fourteenth Amendment?s Equal Protection and Due Process Clauses. The fundamental liberties guaranteed to criminal defendants by the Fourth, Fifth, Sixth, and Eighth Amendments are best understood in the context of the criminal proceeding during which they are normally triggered.