Discovery

Discovery systems commonly list three major remedies for failure to comply with discovery rules: an order to comply, a continuance, and a prohibition against introducing the evidence or calling the witness not properly disclosed. In addition, other remedies are either explicitly authorized by the discovery provisions in some jurisdictions or recognized as an aspect of judicial discretion to control discovery. These other remedies include instructions to the jury regarding adverse inferences it may draw based on discovery violations, contempt sanctions, and, in rare instances, dismissal of the prosecution.

In Illinois v. Taylor, the U.S. Supreme Court answered whether it was constitutional to preclude a defense witness from testifying because of a defense failure to comply with a discovery rule. The Court held that preclusion was a proper remedy in some circumstances and ruled that it did not violate the defendant's constitutional right to present defense evidence. Excluding the testimony of witnesses is not a preferred remedy, but the Court ruled it available for a willful discovery violation calculated to gain a tactical advantage in a situation where compliance with the discovery obligation was simple.

Generally, the defendant's own testimony cannot constitutionally be excluded as a sanction for a discovery violation, but potentially all supporting testimony from other witnesses can be. As noted earlier, whether it is constitutional to use a withdrawn discovery notice, such as a notice of a particular alibi, against the defense to impeach another defense offered at trial remains a matter of debate. Many discovery rules prohibit such use of withdrawn defense notices, but others do not, and some courts have found that use of the withdrawn notice to impeach is proper.