In the 1942 case McNabb et al. v. United States, the Supreme Court ruled that confessions obtained from defendants held in custody for an unreasonable amount of time before being brought before a judge were inadmissible as evidence. The case involved three men who had been arrested and interrogated by federal agents over several days without being taken to court or informed of their rights. They eventually confessed to murder, but later argued that their confessions should not be used against them because they were not promptly arraigned after arrest as required by federal law at the time. The Supreme Court agreed with this argument and reversed their convictions, establishing what came to be known as the "McNabb-Mallory rule". This ruling emphasized due process rights under U.S law and highlighted how police misconduct could lead to exclusion of evidence.

In the dissenting opinion for McNabb et al. v. United States, Justice Owen Roberts disagreed with the majority's decision to exclude confessions obtained during a period of illegal detention from being used as evidence in court trials. He argued that this ruling was not based on any specific constitutional or statutory provision but rather on an arbitrary rule created by the Court itself. According to him, it is Congress' responsibility to legislate rules regarding admissibility of evidence and federal criminal procedure, not the Supreme Court's role. Furthermore, he contended that excluding such confessions could potentially allow guilty individuals to escape punishment due their unlawful arrest or detention which would undermine law enforcement efforts and public safety.