The allowable scope of discovery by defendants is much more limited in
criminal cases. This is rationalized by the high burden of proof that the
prosecutor must meet: even if defendants do nothing in their defense, the
state will still lose unless it convinces the jury of the defendant’s guilt beyond a
reasonable doubt. Under federal law, the defendant need not provide any
testimony to the prosecutor unless the defendant wants to raise a defense of
mental incapacity, alibi, or governmental authority. The courts and legislatures
are also concerned with the reluctance of witnesses to testify if they fear
retaliation. There is also the possibility that if defendants in some cases know
before about adverse testimony before trial, they would attempt to suborn
perjury—get the witnesses to lie or find other persons to lie to contradict them.
In extreme cases, the federal law provides for preventive detention of the
defendant or of the witnesses to prevent witness intimidation or murder.
[United States v. Salerno, 481 U.S. 739 (1987)
Although the defendant does not have a right to all the information that the
government holds, the defendant does have a constitutional right to favorable
evidence that the government holds. [Brady v. Maryland, 373 U.S. 83 (1963)
The difficulty is for the defendant to figure out how to ask for specific evidence
that meets this test when the defendant does not know what evidence the
government is holding. The defendant’s attorney must craft a “Brady request”
that forces the government to either turn over the evidence or risk having their
case reversed on appeal if the evidence comes out at trial or even posttrial.
For reversal, the defendant must show that he or she did not have other notice
of the information. There is no violation “where a defendant knew or should
have known the essential facts permitting him to take advantage of any
exculpatory information, or where the evidence is available from another
source.” [United States v. Clark, 928 F.2d 733, 738 (6th Cir. 1991)
defendant must also show that the evidence that was withheld is “material,” in
that there is a reasonable probability that it would have affected the result of
the trial. [United States v. Bagley, 473 U.S. 667, 682 (1985)
The defendant is entitled to the records of certain of his or her own statements
made to the police and to recorded statements made by witnesses who testify.
These are generally not provided before the trial, but only at the time the
witnesses testify. The government is permitted to give the defendant more
information, and the defendant may petition the judge to order the government
to produce other information. The government has an incentive to provide
additional information because it reduces the defendant’s grounds for appeal
based on withholding exculpatory evidence. This is most important in cases
involving the death penalty where the postconviction review is the most
thorough and the defendant gets the greatest benefit of the doubt as to the
importance of the evidence.