The Eighth Amendment prohibition on “excessive bail”1 is perhaps the least developed of the criminal clauses in the Bill of Rights. The reasons have nothing to do with a scarcity of complaints about excessive bail in the trial courts. At any given time, about 500,000 criminally accused persons languish in jail in the United States, and not only defense lawyers in individual cases, but legal scholars who have studied the broader spectrum of cases regularly contend that many of these detentions are unnecessary. Yet, claims of excessive bail virtually never receive an airing in the Supreme Court, unlike claims, for example, about unreasonable police invasions of privacy, improper police interrogations, or cruel and unusual punishments. The Court has not issued an opinion applying the Excessive Bail Clause in more than 25 years and has rendered only two others in its history, both in the early 1950s.