The Thirteenth Amendment to the U.S. Constitution (ratified in 1865) abolished slavery and involuntary servitude. A joke was posted on Reddit—Jokes on December 7, 2017:
 
“The 13th Amendment makes it illegal to buy people. Apparently, it doesn’t apply to congressmen.”
   
         
Wikipedia: Thirteenth Amendment to the United States Constitution
The Thirteenth Amendment (Amendment XIII) to the United States Constitution abolished slavery and involuntary servitude, except as punishment for a crime. In Congress, it was passed by the Senate on April 8, 1864, and by the House on January 31, 1865. The amendment was ratified by the required number of states on December 6, 1865. On December 18, 1865, Secretary of State William H. Seward proclaimed its adoption. It was the first of the three Reconstruction Amendments adopted following the American Civil War.
 
Reddit—Jokes
The 13th Amendment makes it illegal to buy people.
submitted December 7, 2017 by Datubaman
Apparently, it doesn’t apply to congressmen.
     
Twitter
Bob Kostic
@causticbob
The 13th Amendment makes it illegal to buy people.
Apparently, it doesn’t apply to congressmen.
6:43 AM - 15 Dec 2017
 
Reddit—Oneliners
The 13th Amendment makes it illegal to buy people, but, apparently, it doesn’t apply to congressmen.
submitted March 30, 2018 by madazzahatter
 
Twitter
JokeFarm
@_JokeFarm
The 13th Amendment makes it illegal to buy people, but, apparently, it doesn’t apply to congressmen. #joke #jokes
9:57 AM - 30 Mar 2018
 
Reddit—Cleanjokes
The 13th Amendment makes it illegal to buy people… (self.cleanjokes)
submitted May 10, 2018 by madazzahatter
Apparently, it doesn’t apply to congressmen…