bail, procedure by which a judge or magistrate sets at liberty one who has been arrested or imprisoned, upon receipt of security to ensure the released prisoner’s later appearance in court for further proceedings. Release from custody is ordinarily effected by posting a sum of money, or a bond, although originally bail included the delivery of other forms of property, such as title to real estate. The principal use of bail in modern legal systems is to secure the freedom, pending trial, of one arrested and charged with a criminal offense, although it may also be used in some cases to secure release pending an appeal of a conviction. Subject to jurisdictional variations, its use in civil cases has diminished along with the decline of imprisonment for debt.
The purposes of bail pending trial in criminal cases are to avoid inflicting punishment upon an innocent person (who may be acquitted at trial) and to encourage the unhampered preparation of his defense. The amount of bail is generally set in relation to the gravity of the offense charged and the likelihood of flight, although some magistrates take into account other factors, such as the strength of the evidence, the character of the accused, and the ability of the accused to secure bail. Failure to consider financial ability generated much controversy in the mid-20th century, for bail requirements may discriminate against poor people and certain minority groups who are thus deprived of an equal opportunity to secure their freedom pending trial. Some courts now give special consideration to indigent accused persons who, because of their community standing and past history, are considered likely to appear in court. The court may release the accused on an unsecured promise—i.e., on their own recognizance. Some jurisdictions also permit the accused to post a fraction of the bail, usually 10 percent, in cash with the clerk of the court. A few jurisdictions make it a separate criminal offense to forfeit bail instead of appearing as required. In all jurisdictions an arrest warrant may issue for the accused who has failed to appear in addition to forfeiture of bail.
In legal systems that have a bail procedure, its operation is highly discretionary. If an accused is charged with an offense committed while free on bail, if the arrested person requires police protection, or if evidence reasonably establishes that he committed murder or treason, bail may be denied. Alternatively, bail may be set unusually high. The U.S. Supreme Court held in United States v. Salerno (1987) that bail may also be denied in some limited cases where no conditions of release can reasonably assure the safety of the community or of particular individuals.