Voters in Utah and Nebraska approved measures Tuesday stripping references to slavery from their state constitutions.

In Nebraska, 68 percent of voters approved and 32 percent rejected an amendment to remove language on the use of slavery as a punishment for convicted criminals, Ballotpedia reported.

Voters in Utah came out strongly in favor of a measure to remove slavery language from the state's founding document, with 80 percent in support and 19 percent against.

The passage of the measure will amend Section 21 of Article I of the Utah Constitution, removing language that disallowed slavery "except as a punishment for crime, whereof the party shall have been duly convicted."

The amendment in Nebraska first won approval by state lawmakers in March 2019, scoring a unanimous 44-0 vote, The Associated Press reported.

The Nebraska Constitution has banned slavery and involuntary servitude since 1875, except as a punishment for a crime.

While the provision has not been invoked in recent history, it was once used to force former slaves back into unpaid labor for private parties, and later for convict leasing.

A similar provision was passed in Colorado in 2018, removing language from its state constitution that permitted involuntary servitude as criminal punishments.

The 13th Amendment to the U.S. Constitution, ratified in 1865, says, “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.”