Clue: I don't care who's at fault (2,4)
Answer: SO WHAT
Explanation: Definition: I don't care
An anagram ('fault') of 'who's at'. This puts me in mind (I hope my memory is correct) of a test question on the Second World War in *1066 and Now all This*: "Never in the what of what what has so what been what by so what to so what?"