Kastigar v. United States
Kastigar cited his Fifth Amendment protection against self-incrimination in refusing to testify before a grand jury, even though prosecutors had granted him immunity from the use of his testimony in subsequent criminal proceedings. He was found in contempt of court for failing to testify.
Can the government, by granting immunity from the use of compelled testimony in future prosecutions, force a witness who invokes the Fifth Amendment to testify?
The Court found that compelled testimony is legitimate given the grant of immunity. Justice Powell found that the protections of immunity that a congressional statute provided were "coextensive with the scope of the privilege against self-incrimination" and "sufficient to compel testimony over a claim of the privilege."
