Justice Felix FrankfurterFrankfurter, Felix;Ullman v. United States[Ullman v. United States] wrote the opinion for the 7-2 majority, upholding the Immunity Act. A federal court acting under the Immunity Act ordered defendant Ullman to testify before a grand jury investigating communist activities that potentially endangered national security. Despite having transactional immunity from state or federal prosecution for his compelled testimony, Ullman refused to testify and was imprisoned for six months for contempt of court. On appeal, Ullman said the immunity was incomplete because he still faced potential loss of a job or union membership and public contempt. Frankfurter rejected the argument, pointing out that the Fifth Amendment protected only against criminal prosecution. Justices Hugo L. Black and William O. Douglas dissented.CommunismImmunity against self-incrimination;Ullman v. United States[Ullman v. United States]Congressional power of investigation;Ullman v. United States[Ullman v. United States]Communism

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