United States v. Classic, 313 U.S. 299 (1941), was a decision by the Supreme Court of the United States that the United States Constitution empowered Congress to regulate primary elections and political party nominations procedures, and that the constitutional "right of participation" extended to primary elections "is protected just as is the right to vote at the election, where the primary is by law made an integral part of the election machinery, whether the voter exercises his right in a party primary which invariably, sometimes or never determines the ultimate choice of the representative."