In the United States v. Barnow case of 1915, the Supreme Court ruled on a matter concerning interstate commerce and fraud. The defendant, Mr. Barnow, was involved in a scheme where he would send fraudulent letters across state lines to trick individuals into purchasing stock from his company under false pretenses. He was charged with using the mail system for illegal purposes under federal law but argued that this did not constitute an offense against interstate commerce as defined by Congress at that time. The Supreme Court disagreed with Barnow's argument and upheld his conviction stating that while it is true that Congress cannot regulate all aspects of interstate communication or transactions (such as personal letters), when such communications are used as part of a systematic effort to defraud people out-of-state, they fall within Congressional power to regulate and punish abuses in interstate commerce.

The dissenting opinion in the United States v. Barnow case argued that the defendant's conviction should not have been upheld because it was based on a law that was too vague and broad, potentially infringing upon individual rights. The justice expressed concern over the potential for abuse of such laws by authorities, leading to arbitrary enforcement and punishment. He also pointed out inconsistencies in how similar cases had been handled previously, suggesting a lack of fairness and uniformity in applying this particular law. Furthermore, he disagreed with the majority's interpretation of what constituted "fraudulent intent," arguing that there wasn't enough evidence to prove this element beyond reasonable doubt in Barnow's case.