While one might be shocked at the presentation of such a question about such a historically controversial subject, one might also not be worse off to simply read their Constitution of the United States…
Let’s have a look at the 13th Amendment to the Constitution of the United States:
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.