In Friedberg v. United States, the Supreme Court considered whether a defendant's constitutional rights were violated when he was not allowed to cross-examine a government witness about prior inconsistent statements made before a grand jury. The case involved an individual charged with perjury for allegedly making false statements during his naturalization proceedings. During trial, the prosecution called as its main witness an interpreter who had been present at those proceedings and testified that the defendant had lied under oath. However, when defense counsel sought to question this witness about previous contradictory testimony she gave before a grand jury, the court disallowed it on grounds of irrelevancy. The Supreme Court held that this restriction on cross-examination constituted reversible error because it infringed upon the accused's Sixth Amendment right "to be confronted with witnesses against him." According to Justice Black’s majority opinion, such questioning is essential in order for juries to adequately assess credibility and reliability of witnesses' testimonies; thus denying defendants from doing so deprives them of their fundamental right to fair trial.

In the dissenting opinion for Friedberg v. United States, it was argued that the majority's decision to uphold Friedberg's conviction based on evidence obtained through wiretapping violated his Fourth Amendment rights against unreasonable searches and seizures. The dissenting justices contended that the use of wiretap evidence should be considered unconstitutional because it involves an invasion of privacy without a warrant or probable cause. They also expressed concern about the potential for abuse if law enforcement agencies are allowed to use such methods without proper oversight or restrictions. Furthermore, they disagreed with the majority's view that Congress had implicitly approved this practice by not explicitly prohibiting it in legislation, arguing instead that legislative silence should not be interpreted as approval.