In the 1955 case Parr v. United States, George J. Parr and Archer Parr were convicted of conspiracy to defraud the U.S government by manipulating votes in Duval County, Texas during federal elections from 1946-1952. The defendants argued that they had not committed a federal offense as their actions only affected state elections and did not involve any direct fraud against the U.S government or its agencies. However, the Supreme Court ruled against them stating that since federal funds were used for election expenses such as printing ballots and paying poll workers, any fraudulent activity affecting these elections constituted a crime under applicable federal statutes aimed at protecting public money or property from fraudulent practices.

In the dissenting opinion for Parr v. United States, Justice Clark disagreed with the majority's decision to reverse and remand the case back to a lower court. He argued that there was sufficient evidence presented at trial to support a conviction of mail fraud against Parr. According to him, it was clear from the record that Parr had used his position as superintendent of schools in San Antonio, Texas, and president of Alamo Heights School District Board of Trustees, to defraud both entities by using their funds for personal expenses without their knowledge or consent. This included mailing checks drawn on school district accounts for unauthorized purchases which constituted mail fraud according to federal law. Furthermore, he believed that any errors made during jury instructions were harmless beyond reasonable doubt because they did not affect substantial rights or result in miscarriage of justice given overwhelming evidence against Parr.