On November 21, 1972 Samuel Lewis Popkin, an assistant professor of government at Harvard University, was imprisoned in the federal section of the Norfolk County jail in Dedham, Massachusetts, under a contempt order of the United States District Court, District of Massachusetts. He was imprisoned for contempt of court for refusal to answer several questions before a federal grand jury investigating the publication of the Pentagon Papers. In the course of the grand jury proceedings Popkin asserted a right under the First Amendment to refuse to answer questions concerning the identity of confidential sources and the content of his opinions and data developed in the course of research on and in Vietnam. He refused to answer the questions on the grounds that they violated his rights to freedom of the press, freedom of speech, and freedom of assembly under the First Amendment in the absence of a showing by the government that the information sought was relevant and necessary to the government's investigation.

On November 28, 1972, the grand jury was discharged at the government's request and Popkin was released from jail.

In early January, 1973, Popkin filed a petition for a writ of certiorari asking the Supreme Court to review the case. The petition was denied by the Court in April, 1973.

The Popkin case is the first on record in American law in which the question of a scholar's right to the confidentiality of his sources and data has been raised and decided, at least in part, on the merits.