The United States v. Classic et al., 1940, was a landmark Supreme Court case that expanded the scope of federal jurisdiction over primary elections. The defendants, election commissioners in Louisiana, were charged with altering and falsifying ballots during a Democratic Party primary for the U.S House of Representatives. They argued that primaries weren't covered under Article I Section 4 or Section 2 of the Constitution which only mentioned "Elections". However, the court ruled against them stating that because Louisiana law effectively determined final election outcomes through its primary results (due to one-party dominance), these primaries constituted an integral part of standard electoral procedure and thus fell within constitutional purview. This ruling established precedent for federal intervention in state-run elections when necessary to protect citizens' voting rights.

In the dissenting opinion for United States v. Classic et al., Justice James Clark McReynolds argued that the majority's interpretation of Article I, Section 4 and Section 2 of the Constitution was incorrect. He contended that these sections do not grant Congress power to regulate primary elections within states, as they only pertain to final elections for Senators and Representatives. Furthermore, he asserted that Louisiana law did not consider primaries part of a general election process but rather an internal party affair; thus federal regulation would infringe upon state rights. Additionally, he disagreed with applying criminal sanctions under Sections 19 and 20 of the Criminal Code in this case because it could potentially lead to federal interference in local affairs beyond what is constitutionally permissible.