make (a) nonsense of (something)
To treat something serious or important in a silly or ridiculous manner; to make a mockery of something. The candidate has been making a nonsense of the whole political process, but for some reason many voters feel that that is just what's needed. I don't appreciate you making nonsense of this class with your rude remarks and obnoxious behavior.
make (a) ˈnonsense of something
reduce the value of something by a lot; make something seem ridiculous: If people can bribe police officers, it makes a complete nonsense of the legal system.