## Facts

- A corporation and two employees were indicted in federal court for conspiracy and for concealing material facts within the jurisdiction of a federal agency, under 18 U.S.C. §§ 371 and 1001.
- The defendants were tried before a jury in a federal district court with jurisdiction over the parties and subject matter.
- After about seven days of trial, with three government witnesses having testified and a fourth on the stand, the district judge directed the jury to return verdicts of acquittal for all defendants.
- A formal judgment of acquittal was entered.
- The judge’s stated basis was one or both of: alleged prosecutorial misconduct and asserted lack of credibility of prosecution witnesses.

## Issues

1. Whether the Double Jeopardy Clause bars the government from using mandamus to vacate a directed midtrial judgment of acquittal and obtain a retrial.
2. Whether the asserted impropriety or legal error underlying an acquittal permits appellate nullification of that acquittal without violating the Fifth Amendment.

## Decision

- The Supreme Court reversed the court of appeals’ issuance of mandamus.
- The Court held that vacating the judgment of acquittal and subjecting defendants to retrial would violate the Fifth Amendment’s Double Jeopardy Clause.
- The acquittals remained in effect, notwithstanding any error in the trial judge’s reasons for directing them.

## Legal Principles

- Once a defendant has been acquitted by a court of competent jurisdiction after jeopardy has attached, the Double Jeopardy Clause prohibits a second trial for the same offense.
- A judgment of acquittal is final for double jeopardy purposes even if entered prematurely, on mistaken legal grounds, or in response to perceived prosecutorial misconduct.
- Extraordinary writs such as mandamus cannot be used to circumvent double jeopardy by undoing an acquittal and ordering a new trial.
- Appellate authority to correct trial-court error differs when the correction would require further proceedings on guilt after an acquittal; double jeopardy forecloses that remedy.

## Conclusion

The Court held that the government could not set aside a midtrial directed acquittal through mandamus and retry the defendants, because a final acquittal entered after jeopardy attached is insulated from further prosecution even if the acquittal was erroneous.


Fong Foo v. United States, 369 U.S. 141 (1962)