The thirteenth amendment makes it unconstitutional to

The Thirteenth Amendment

Section 1.
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.
Section 2.
Congress shall have power to enforce this article by appropriate legislation.

Passed by Congress January 31, 1865. Ratified December 6, 1865.

Basically you can't force anyone to work only the law enforcement and it has to be a punishment chosen by the court when that person has fully went through their trail.