In the United States v. Harris case of 1970, the U.S Supreme Court ruled that a federal statute making it a crime to receive, possess or transport in interstate commerce any firearm which has had its serial number removed or altered is constitutional and does not violate an individual's Fifth Amendment rights against self-incrimination. The defendant, Harris, was convicted under this law after he was found with two firearms with obliterated serial numbers during an unrelated search by police officers for stolen property. He appealed his conviction arguing that it violated his right against self-incrimination as he would be forced to disclose illegal activity (possession of guns with tampered serial numbers) if questioned about them by authorities. However, the court rejected this argument stating that possession of such items did not inherently incriminate him but rather their unlawful use would.

In the dissenting opinion for United States v. Harris, Justice Harlan argued that the majority's decision to uphold a search warrant based on an informant's tip violated Fourth Amendment protections against unreasonable searches and seizures. He contended that allowing police officers to obtain warrants based solely on hearsay evidence from informants undermined the constitutional requirement of probable cause. Harlan further criticized the majority for failing to establish clear guidelines about what constitutes a reliable informant, leaving too much discretion in hands of law enforcement agencies which could lead to potential abuses of power. He also expressed concern that this ruling would erode public trust in law enforcement by enabling them to conduct invasive searches without sufficient justification or oversight.