In the case of Wainer et al. v. United States, 1936, the appellants were convicted for conspiracy to violate provisions of the National Prohibition Act by selling alcohol illegally in violation of federal law. The Supreme Court was asked to determine whether a conviction could be upheld based on evidence obtained through wiretapping without a warrant, which was alleged as an invasion of privacy and thus unconstitutional under the Fourth Amendment. The court held that such evidence is admissible because it did not involve physical intrusion into private property or seizure of tangible material effects; rather it involved only conversations overheard by government agents who had tapped public telephone wires outside defendants' premises. This decision reflected prevailing legal understanding at that time about what constituted "searches" and "seizures" within meaning of Fourth Amendment - namely, those involving physical trespass onto private property or removal/seizure tangible items therefrom.

The dissenting opinion in Wainer et al. v. United States argued that the majority's decision to uphold the defendants' convictions for conspiracy to violate Prohibition laws was flawed due to insufficient evidence of a single, overarching conspiracy involving all accused parties. The dissent contended that while there may have been multiple smaller conspiracies between various combinations of individuals, no concrete proof existed demonstrating a unified agreement among all involved parties as required by law for conviction on charges of broad-scale conspiracy. Furthermore, it was suggested that the lower court had erred in its instructions to the jury regarding what constituted sufficient evidence for such a charge and this error could have influenced their verdict unfairly against some or all defendants.