Five U.S. states will vote this November on whether to eliminate language in their state constitutions that allows a form of slavery as a punishment in prisons, an exception written into the 13th Amendment abolishing slavery when it passed more than 150 years ago.

Experts say the bills - which are on the ballot in Tennessee, Alabama, Louisiana, Oregon and Vermont - could buoy growing prison-reform efforts in a country where roughly 800,000 prisoners work, often being forced to do so and for little to no pay. The 13th Amendment of the U.S. Constitution bans slavery or involuntary servitude, except when it is used as punishment for a crime.

If passed, the proposals would wholly abolish slavery in those states, though they would not automatically change protocols on prison labor or inmate pay. While not all states have constitutions that explicitly permit slavery and involuntary servitude as criminal punishments, only three have passed similar legislation to remove the exception - Colorado was the first to do so in 2018, followed by Nebraska and Utah two years later.

"This is the beginning of a wave," said Sharon Dolovich, a law professor at the University of California at Los Angeles and an expert on prison law. "I suspect that in 10 years maybe we'll be horrified that, in 2022, most states had this on the books."

Experts say that the bills, in spirit, open a conversation about greater issues with the U.S. prison system, which has the highest incarceration rate of any country in the world and disproportionately imprisons Black people, according to the American Civil Liberties Union.

"We have to come to terms with the fact that the very amendment that freed the slaves has a clause to re-enslave them," said Robert Chase, an associate professor at Stony Brook University and the director of Historians Against Slavery, a collective of scholars and activists. "For an entire generation, it put Black men and women back into slavery by incarcerating them and selling their labor to private corporations."

Prison workers in the U.S. produce about $2 billion a year in goods and commodities and more than $9 billion a year in services that maintain prisons, according to the ACLU. Meanwhile, they're paid nothing in seven states and an average of about 52 cents per hour nationally, according to a report published by the group earlier this year. In many cases, they keep less than half of what they earn after deductions for tax, room and board, and other fees.

Prisoners who refuse to work are also often punished, Chase and Dolovich said, sometimes with solitary confinement or the erasure of sentence reductions for good behavior.

In 2002, the Supreme Court reviewed a case, broadly about prison officials' immunity from liability, in which an Alabama inmate was chained to a hitching post in a standing position for seven hours under the sun. The post was used as a punishment for those who refused to work as part of a chain gang, and the Supreme Court determined that it qualified as unconstitutional "cruel and unusual punishment."

In 2016, forced labor and poor wages ultimately led to the largest prison strike in U.S. history, with an estimated 24,000 inmates refusing to work in at least 12 states. Last month, inmates in Alabama also went on strike, paralyzing prison operations by refusing to work in laundry rooms or janitorial services, the Associated Press reported.

"If we think about striking down slavery, we have to address not just the wage issue, but the issue of human rights in our prisons," Chase said. "These are ongoing struggles over not just prison labor, but the entirely human-degrading system of violence that is central to how we've structured our prisons."

The five states' bills do not make it clear whether paying an inmate a few cents per hour would qualify as slavery. Earlier this year, California struck down a similar measure that would abolish indentured servitude, fearing the costs the state would incur if it had to pay prisoners the minimum wage.

If passed, the bills could give lawyers more license to pursue greater rights and higher pay for U.S. prisoners; Dolovich said that paying inmates below the minimum-wage protections set by each state is arguably "a species of slavery."

"It'll be a fight in court. This question will be manifested by lawyers bringing cases on behalf of incarcerated workers," she said. "It's a hopeful sign for me."