In the United States v. Harsha case of 1898, the Supreme Court ruled on a matter involving fraudulent use of mail. The defendant, Mr. Harsha, was accused of using mail to defraud people by selling them counterfeit money detectors and other related items that were essentially worthless. He argued that he could not be prosecuted because his actions did not involve any form of interstate commerce which would bring it under federal jurisdiction as per the Commerce Clause in the Constitution. The Supreme Court disagreed with Harsha's argument and held him accountable for his fraudulent activities through mail regardless if they involved interstate commerce or not. They reasoned that while Congress may have limited powers over commerce between states, it has broad power to regulate all aspects concerning post offices and postal roads including their misuse for frauds like those committed by Mr.Harsha. This ruling established an important precedent regarding federal authority over crimes committed via U.S Postal Service irrespective of whether they directly affect interstate trade or not.

The dissenting opinion in the United States v. Harsha case argued that the defendant, a postmaster accused of embezzling funds, should not have been convicted based on circumstantial evidence alone. The dissenting justices believed there was insufficient direct evidence to prove beyond reasonable doubt that Harsha had committed the crime he was charged with. They contended that while discrepancies existed between his accounts and actual cash balance, these could be due to errors or negligence rather than criminal intent. Furthermore, they pointed out inconsistencies in testimonies from government witnesses which cast further doubts on Harsha's guilt. Therefore, they disagreed with majority's decision to uphold his conviction.