Discovery

Those familiar with civil discovery will immediately notice that several of its most important discovery devices—interrogatories, depositions, and demands for admission—are either completely absent from criminal discovery or are available in only a handful of jurisdictions. The pattern in criminal discovery is for the rules or statutes to require the disclosure of specific types of information, rather than to authorize the use of broad discovery devices that would likely produce such information and much more. In the areas of alibi (noted above) and insanity (discussed below) discovery rules specifically applicable to these defenses are the norm. One of the major reasons for general difference between civil and criminal discovery is the existence of the defendant's constitutional privilege against compulsory self-incrimination.

While Williams decided that the state could discover from defendants information that they would ultimately provide as a defense, adversarial interrogation of defendants under threat of sanctions and any requirement that defendants admit parts of the prosecution's case are not compatible with the Fifth Amendment. As a result, depositions, interrogatories, and demands for admission directed at the defendant are not available tools. Depositions of other witnesses do not directly offend the Constitution, however.

While used as a discovery device in a handful of states, depositions are used principally to preserve testimony of witnesses who are expected to be unavailable at trial. One reason depositions are not generally available is that most criminal defendants are indigent, and as a result, the cost to the party of taking depositions does not act as a check on excessive use as it does in civil cases. Concern about imposing additional obligations on witnesses, who are often already reticent to become involved in criminal cases and particularly to have contact with the defendant, militates against expanded use of depositions. This concern, highlighted by the victims' rights movement, is particularly acute when a victim is also a witness in the case. Nevertheless, discovery depositions of witnesses other than the defendant (and sometimes victims) are used in a handful of states in criminal cases.