There’s one form of slavery that the constitution shockingly still protects—that of convicted felons, who can be forced into work as punishment for a crime. This Wednesday, Democratic members of the House and Senate introduced a joint resolution to prohibit the exploitation of prison labor which the constitution has allowed well into the 21st century. “This change to the 13th Amendment will finally, fully rid our nation of a form of legalized slavery,” Sen. Chris Van Hollen (D-MD) said in a statement. He has signed on to the resolution in the Senate, along with Bernie Sanders (I-VT) and Ed Markey (D-MA). Rep. William Lacy Clay (D-MO) is leading the version in the House. It’s uncommon but not impossible to make changes to a constitutional amendment, and multiple advocacy groups have already spoken out in support of the resolution. Among those are The Sentencing Project, the Anti-Recidivism Coalition, and the Color of Change. Around half of U.S. states already ban or do not mention the exploitation of prison labor in their constitutions. Nebraska and Utah struck down similar language in their state constitutions last month.