Blau v. United States

Background

Mrs. Blau, a woman called as a witness before a federal grand jury in Denver, was asked whether she knew officers, the organization, or whether she had been employed by the Communist Party of Colorado and about party books and records. She refused to answer those questions, invoking the constitutional privilege against self‑incrimination, and repeated that refusal before the district judge. The judge held her in contempt and sentenced her to one year in jail. The Court of Appeals affirmed, and the Supreme Court agreed to review the case because the conviction appeared to deny Fifth Amendment rights and conflicted with other circuit decisions.

Reasoning

The central question was whether a witness may refuse grand jury questions when truthful answers could reasonably lead to criminal charges under the Smith Act, which then made advocacy and membership in certain groups criminal. The Court explained that answers about Communist Party membership or employment could supply a link in the chain of evidence needed for prosecution. Relying on longstanding precedents going back to decisions by Chief Justice Marshall and later cases, the Court held that the Constitution protects a witness who reasonably fears prosecution and reversed the contempt conviction.

Real world impact

The ruling protects witnesses called by federal grand juries from being forced to answer questions that could reasonably lead to prosecution under criminal statutes like the Smith Act. People questioned about membership or activities in groups that may be criminalized can invoke the Fifth Amendment without facing contempt for silence. The decision reaffirms long‑standing limits on courts’ power to compel testimony in criminal investigations.