Amendment 28:
"The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people."
Since the 13th Amendment reads, "Neither slavery nor involuntary servitude, EXCEPT AS A PUNISHMENT FOR A CRIME WHEREOF THE PARTY SHALL HAVE BEEN DULY CONVICTED, shall exist within the United States, or any place subject to their jurisdiction."
Since many people, especially people of color, are imprisoned for non-violent crimes such as recreation drug use, where their labor is then exploited.