In Gojack v. United States (1965), the U.S. Supreme Court ruled in favor of John T. Gojack, a labor union official who was convicted for perjury during an investigation by the House Committee on Un-American Activities (HUAC). The case centered around whether or not questions asked by HUAC were pertinent to its inquiry and if they violated Gojack's Fifth Amendment rights against self-incrimination. The court found that many of the questions posed to him were too vague and broad, making it impossible for him to know what subject matter he should have been prepared to discuss, thus violating his constitutional rights. Therefore, his conviction was overturned.

In the dissenting opinion for Gojack v. United States, Justice Harlan argued that the majority's decision to reverse Gojack's conviction was based on a misinterpretation of Watkins v. United States and Barenblatt v. Four American Boys Productions, Inc., two precedents concerning congressional investigations' scope and limits. He contended that these cases did not establish an absolute rule requiring explicit authorization by Congress for every question asked in its investigations but rather emphasized the importance of relevance to legislative purposes in determining whether questions were within investigative authority bounds. According to Justice Harlan, there was no doubt about the pertinence of questions asked from Gojack regarding his Communist Party affiliations as they related directly to ongoing legislation concerning internal security matters at that time; hence he should have been held accountable for refusing to answer them before a congressional committee.