In the United States v. Johnson et al., 1967, the Supreme Court ruled that Congress did not intend to exclude unlawfully obtained evidence from use in a grand jury proceeding when it enacted legislation governing federal wiretapping and electronic eavesdropping (Omnibus Crime Control Act). The case involved two defendants who were indicted for conspiracy to defraud the U.S. government based on evidence gathered through unauthorized microphone surveillance by IRS agents. The defendants moved to suppress this evidence, arguing its acquisition violated their Fourth Amendment rights against unreasonable searches and seizures. However, the court held that while such surveillance was indeed unlawful under existing statutes, there was no legislative intent to extend exclusionary rules of trial proceedings into grand jury hearings. Therefore, despite being illegally obtained, the audio recordings could be used as part of grand jury deliberations.

In the dissenting opinion for United States v. Johnson et al., 1967, it was argued that the majority's decision to exclude evidence obtained through wiretapping violated long-standing principles of criminal law and procedure. The dissenters believed that the exclusionary rule should not apply in this case because it was designed to deter police misconduct, not punish inadvertent mistakes made by officers acting in good faith. They also pointed out that applying such a strict interpretation of the Fourth Amendment could potentially hinder effective law enforcement and undermine public safety. Furthermore, they disagreed with the majority's assertion that Congress had intended to completely prohibit all use of wiretap evidence when it passed Title III of Omnibus Crime Control Act; instead, they interpreted Congressional intent as allowing such evidence if obtained properly under state law or federal guidelines.