It isn't, which is why the 13th amendment (which bans other forms of slavery) explicitly permits it. Some members from both houses of Congress have recently pr

It isn't, which is why the 13th amendment (which bans other forms of slavery) explicitly permits it. Some members from both houses of Congress have recently proposed a constitutional amendment to change this: https://www.merkley.senate.gov/imo/media/doc/The%20Abolition%20Amendment%20Text.pdf https://www.merkley.senate.gov/imo/media/doc/The%20Abolition...