In a lawsuit filed this week, a group of current and former Alabama prisoners say they have been coerced into providing cheap labor to the state and to private employers.

The U.S. Constitution bans slavery except as punishment for a crime. A growing number of states have tried to address this in their own constitutions, but prisoners say the only change is on paper.

Congressional Democrats seek to remove the "punishment" clause from the 13th Amendment which allows members of prison populations to be used as cheap and free labor.