According to the Oxford Living Dictionaries:

perversion

noun
1  Distortion or corruption of the original course, meaning, or state of something.

 

 Some examples:

 

The American fascists are most easily recognized by their deliberate perversion of truth and fact. Their newspapers and propaganda carefully cultivate every fissure of disunity, every crack in the common front against fascism.
– Henry Wallace

 

No oppression is so heavy or lasting as that which is inflicted by the perversion and exorbitance of legal authority.
– Samuel Johnson

 

When you have both parties who will not find ways to compromise, who won’t meet in the middle, you have paralysis. It’s the perversion of idealism.
– Beau Willimon

 

We the people are the rightful masters of both Congress and the courts, not to overthrow the Constitution but to overthrow the men who pervert the Constitution.
– Abraham Lincoln