Guinn v. United States (1915) held the “grandfather clause” enacted by the Oklahoma State Legislature invalid because it violated the Fifteenth Amendment to the United States Constitution. The Fifteenth Amendment, the last of three post-Civil War Amendments ratified to end slavery, endowed the rights of citizenship and the right to vote on freed African American slaves.  The amendment specifically declared that the rights of citizens of the United States to vote shall not be denied or abridged by the United States or by any state on account of race, color or previous condition of servitude, and that Congress shall have power to enforce this Article by appropriate legislation. Continue reading Revisit: GUINN V. UNITED STATES (1915)