The Eighth Amendment, in part, provides constitutional protection against excessive bail, including the practical denial of bail by fixing its amount unreasonably high, as decided in United States v. Motlow, 10 F.2d 657 (1926).
Although the Eighth Amendment protects against excessive bail, there is not an absolute right to bail, as noted in The Bail Reform Act, 18 USC Chapter 207 (1984). Section 3142 of the Act denies bail to certain defendants pending trial, specifically denying bail to defendants likely to flee or pose a danger to society. This includes defendants charged with: a crime of violence; an offense where the maximum sentence is life imprisonment or death; certain drug offenses; repeat felony offenders; or a defendant who poses a serious risk of flight. The court conducts a special hearing to determine whether the defendant fits within these categories; anyone who is not likely to flee and does not pose a danger to society must be offered bail while pending trial.
Section 3143 governs the rules for offenders found guilty of a crime who are pending an appeal. Section 3143(a)(1) denies bail to offenders found guilty of non-enumerated crimes unless there is clear and convincing evidence that the person is unlikely to flee or be a danger if released. Section 3143(a)(2) denies bail to offenders found guilty of certain enumerated offenses, including a crime of violence; certain drug offenses; or repeat felony offenders who are pending appeal. The offender must be detained unless there is clear and convincing evidence that the person is unlikely to flee or be a danger if released and there is either: a substantial likelihood that an acquittal or new trial will be granted, or a Government attorney recommends against imprisonment.
The Supreme Court upheld the constitutionality of the Bail Reform Act of 1984 in United States v. Salerno, 481 U.S. 739 (1987). The Court determined that the Eighth Amendment places a restriction on the amount of bail set, so bail cannot place excessive restrictions on a defendant in relation to the perceived evil. Thus, the amount of bail cannot be set to an amount higher than what is necessary to prevent the perceived evil. The Eighth Amendment does not, however, restrict the factors that may be considered when determining bail. The court, for example, may consider risk of flight when determining the amount of bail. The Court also noted that, even if the Bail Reform Act could be hypothetically unconstitutional, this was insufficient to render the entire statute invalid.
As the Eighth Amendment only provides a constitutional protection for the amount of bail set, there is no constitutional protection for receiving speedy bail. In Fields v. Henry County, 701 F.3d 180 (2012), the Sixth Circuit held it was constitutional to impose a requirement of an automatic twelve hour holding period for domestic assault offenders before bail.