In the United States v. Ryan case in 1931, the Supreme Court ruled that a federal grand jury could not be compelled to hear evidence from a person under investigation but not yet indicted. The defendant, James A. Ryan, was being investigated for potential violations of Prohibition laws and sought to present his own exculpatory evidence before the grand jury considering his indictment. However, he was denied this opportunity by both lower courts and ultimately by the Supreme Court as well. The court held that there is no constitutional right or statutory provision allowing an individual who is merely under investigation (and not yet charged) to insist on presenting their own evidence before a grand jury.

In the dissenting opinion for United States v. Ryan, Justice Stone argued that the majority's interpretation of the law was too narrow and failed to consider its broader implications. He contended that by ruling in favor of Ryan, who had been charged with conspiracy to defraud the U.S government through a mail fraud scheme, they were effectively allowing individuals involved in such schemes to escape punishment if their plans did not fully materialize into action. This view contradicted previous court rulings which held that conspiracies themselves were punishable offenses regardless of whether or not they resulted in actual harm. Furthermore, he believed this decision undermined Congress' intent when it enacted laws against mail fraud and conspiracy as separate crimes - each carrying distinct penalties - thereby weakening federal efforts to combat these types of criminal activities.