Question

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.
what loophole in section 1 of the amendment (defined above) allowed prisoners to be rented out to companies for heavy labor?

Explanation:

The 13th Amendment to the U.S. Constitution abolished slavery and involuntary servitude, except as a punishment for crime. The exception clause allows prisoners to be used for labor, which has been exploited in the form of convict - leasing where prisoners are rented out to companies for heavy labor.

Answer:

Convict Leasing