body: I remember long ago I was watching one of those judge Judy type shows and an interesting case came up. Two roommates came to court because they had a valid rent agreement but the one housemate was smoking marijuana. The other one left the house and refused to pay his part of the rent for which he got sued.
  
  
  The jist of the ruling was that if the judge enforced this valid rent agreement, he would force the defendant to be an accomplice to drug usage. If he would then fail a drug test his chance at gainful employment would be greatly diminished which would also be unfair to him.
  
  
  It was a loophole and he found it. The judge remarking that if you want your roommate to pay his rent, don't do drugs. I would love to know what that legal principle is called.
  
  
  
title: What is the concept of by enforcing the law a person cannot be forced to break the law called?