LINCOLN, Neb. (AP) – Nebraska voters will get the chance in 2020 to repeal a state constitutional amendment that allows people to be enslaved as punishment for a crime.

The measure won final approval from lawmakers Thursday on a 44-0 vote.

Nebraska’s Constitution has banned slavery and involuntary servitude since 1875, except as punishment for a crime. Supporters say that provision hasn’t been used in recent history, but was once invoked to force former slaves back into unpaid labor for private parties, a system known as convict leasing.

The measure will appear on the November 2020 general election ballot. Its sponsor, Sen. Justin Wayne of Omaha, says the amendment sends an important message about Nebraska’s values.

Some senators have voiced worries about the message that would be sent if voters reject the repeal measure.