A mistrial occurs when 1) a jury is unable to reach a verdict and there must be a new trial with a new jury; 2) there is a serious procedural error or misconduct that would result in an unfair trial, and the judge adjourns the case without a decision on the merits and awards a new trial. See, e.g. Williamson v. United States, 512 U.S. 594 (1994).

See Category: Courts and Procedure