United States v. Williams

Summary

The Court held that federal courts cannot use their inherent supervisory authority to require prosecutors to present substantial exculpatory evidence to a grand jury or dismiss an otherwise valid indictment for failure to do so. The grand jury is institutionally independent of the courts, and such a disclosure requirement would improperly transform its accusatory function into an adjudicatory one. The Court also held that review was appropriate because the Court of Appeals had decided the issue, although the Government had not contested the controlling circuit precedent in this litigation. Justice Stevens dissented, joined by Justices Blackmun and O'Connor throughout and Justice Thomas in Parts II and III. Stevens would dismiss certiorari as improvidently granted because the Government had not challenged the rule below; on the merits, the dissent maintained that courts may remedy prejudicial prosecutorial misconduct and enforce disclosure of evidence that would plainly preclude probable cause.