In order to extend the civil rights of slaves after the civil war, the united states

The 13th, 14th, and 15th Amendments, known collectively as the Civil War Amendments, were designed to ensure equality for recently emancipated slaves.
The 13th Amendment banned slavery and all involuntary servitude, except in the case of punishment for a crime.
The 14th Amendment defined a citizen as any person born in or naturalized in the U.S.
The 15th Amendment prohibited governments from denying U.S. citizens the right to vote based on race, color, or past servitude.