One hundred fifty years ago the Civil War in America was started and fought with the express primary purpose to abolish chattel slavery in the Antebellum South, Territories, and in all States. Chattel slavery was said to have been abolished with the Thirteenth Amendment to the United States Constitution (1865):
"Neither slavery nor involuntary servitude, EXCEPT AS A PUNISHMENT FOR CRIME WHEREOF THE PARTY SHALL HAVE BEEN DULY CONVICTED, shall exist within the United States, or any place subject to their jurisdiction." (caps added to emphasize the exception for slavery as a punishment for crime)
So, while chattel slavery was prohibited, "...slavery...as a punishment for crime..." expanded throughout all states and territories.
"Neither slavery nor involuntary servitude, EXCEPT AS A PUNISHMENT FOR CRIME WHEREOF THE PARTY SHALL HAVE BEEN DULY CONVICTED, shall exist within the United States, or any place subject to their jurisdiction." (caps added to emphasize the exception for slavery as a punishment for crime)
So, while chattel slavery was prohibited, "...slavery...as a punishment for crime..." expanded throughout all states and territories.