Burks (defendant) was tried for bank robbery in federal court. Burks raised an insanity defense, but the court refused to grant a judgment of acquittal before sending the question to the jury. The jury convicted Burks, and Burks moved the court to grant a new trial on the ground that the evidence against him was inadequate. The trial court denied the motion, and Burks appealed. The court of appeals held that Burks had made a prima facie showing of insanity and that the government did not present sufficient evidence to rebut that showing beyond a reasonable doubt. The appellate court reversed and remanded the case to the district court to decide whether to direct a verdict of acquittal or order a retrial. The United States Supreme Court granted certiorari to consider whether Burks’ retrial is constitutional.