Oregon, Texas, Arizona, and Idaho challenged sections of the Voting Rights Act Amendments of 1970 in this Supreme Court case decided December 21, 1970. The states disputed Congress's authority to lower the voting age from 21 to 18. The deeply divided Court ruled that Congress could constitutionally lower the voting age to 18 in federal elections but not in state and local elections.
None of the justices' opinions garnered a majority of votes. Justices William O. Douglas, William J. Brennan Jr., Byron White, and Thurgood Marshall agreed Congress could lower the minimum voting age in both federal and state elections, but they couldn't convince a fifth justice.
The ruling meant states faced maintaining two sets of registration books and running separate election systems for federal elections versus all other elections. Less than seven months later, the 26th Amendment superseded Oregon v. Mitchell by establishing 18 as the minimum voting age for all elections nationwide.