Over 150 years after U.S. President Abraham Lincoln issued a proclamation freeing slaves, voters in the Southern state of Tennessee have passed a measure officially banning all forms of slavery, including as a punishment for crimes.

Under the ballot measure, passed Tuesday alongside midterm congressional races, a section of the state Constitution allowing slavery "as punishment for a person who has been duly convicted of crime" has been removed, according to the Tennessee Secretary of State’s Office.

Now the relevant section – passed with 79.54% of the vote – says "Slavery and involuntary servitude are forever prohibited. Nothing in this section shall prohibit an inmate from working when the inmate has been duly convicted of a crime."

Although the 13th Amendment to the U.S. Constitution, passed in December 1865 – months after Lincoln was assassinated – already abolished slavery, it includes similar language allowing for "involuntary servitude" to be imposed as punishment for crimes.

Along with Tennessee, banning all forms of slavery was on the ballots on Tuesday in the Southern states of Louisiana and Alabama – both former Confederate States, which declared their secession from the U.S. in 1861-1865 over the right to hold slaves – as well as Oregon (Pacific Northwest), and Vermont (New England).

Similar measures were also approved in Alabama and Vermont, while voters in Louisiana rejected them.

Votes in favor of a similar anti-slavery ballot initiative were in the lead in Oregon.

Advocates of criminal justice reform have long argued that unpaid work for inmates amounts to a form of slavery, as far more Black Americans go to prison as a proportion of their population for similar offenses than white Americans do.