"Well for one, the 13th amendment to the constitution of the US which abolished slavery - did not abolish slavery for those convicted of a crime."

Next Quote

Abolish slavery tomorrow, and not a sentence or syllable of the Constitution need be altered. It was purposely so framed as to give no claim, no sanction to the claim, of property in man. If in its origin slavery had any relation to the government, it was only as the scaffolding to the magnificent structure, to be removed as soon as the building was completed.

— Frederick Douglass