Authoritarian unit involved in unstable Atlanta riot (12)
I believe the answer is:
totalitarian
'authoritarian' is the definition.
(thesaurus)
'unit involved in unstable atlanta riot' is the wordplay.
I cannot quite see how this works, but
'unit' could be 'total' (total is a kind of unit) and 'total' is located in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for totalitarian that I've seen before include "Of ultimate-State-control system" , "Tyrannical" , "One-party" , "far from liberal" , "(Of states) extremely dictatorial" .)