The most important general limitation in both state and federal constitutions, applicable in criminal prosecutions as well as in civil suits, is the guaranty found in Amendment V, and in similar provisions in state constitutions, against depriving " any person of life, liberty, or property without due process of law." This restriction is specifically imposed on the states in Amendment XIV (see below, ch. xliv). It is difficult to describe in a very definite way the essentials of due process of law in criminal cases. It was no doubt intended by the use of this language to preserve the common-law methods of procedure for the punishment of crimes, which involve usually some form of accusation on oath before a magistrate; the issuance by such magistrate of a warrant for the arrest of the accused; a preliminary investigation by the magistrate to determine whether the accused shall be held under bail or otherwise to appear before the grand jury; the hearing of evidence by the grand jury to determine whether there is such reasonable ground to believe the accused to be guilty as to justify the finding of an indictment against him; trial by jury on the charge made in the indictment; sentence by the court to a specified punishment on a verdict of guilty; and execution of the sentence imposed by the court.

These are the usual steps as to crimes of a graver nature designated as felonies; but the preliminary proceedings with relation to the issuance of a warrant of arrest are not regarded as essential steps and may be omitted, for the charge can be made directly to the grand jury, or the grand jury can investigate on its own motion, and a warrant of arrest can be issued in the first instance by the court to which the indictment is returned. The essential steps, therefore, as to felonies are, so far as the protection of the rights of the accused may be concerned, indictment by grand jury, trial by jury, and sentence on verdict of guilty. But in case of crimes involving a lesser degree of criminality, accusation by information may be substituted for indictment by grand jury, and indeed some petty crimes can be punished on trial before a magistrate without a jury. Therefore, it cannot be said that in all criminal cases indictment and jury trial are essential to due process of law.

It may, however, safely be stated that the accused in any criminal proceeding is entitled to know what acts are charged as constituting the crime for which he is put on trial and to an investigation of these facts on evidence received in a judicial tribunal governed by the rules of evidence generally recognized by courts, and to be convicted only when the evidence establishes his guilt beyond a reasonable doubt. These, therefore, are the essential features of due process of law in criminal prosecutions. Certain specific restrictions with reference to each of these steps in the procedure must now be separately considered.