Still do. Slavery is perfectly legal in modern day USA, it's enshrined in the constitution
> 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.
Which is functionally the same as
> slavery or involuntary servitude, 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.