Much ado about Republican as dystopian leader (3,7)
I believe the answer is:
big brother
'dystopian leader' is the definition.
(leader in the novel Nineteen Eighty-Four)
'much ado about republican' is the wordplay.
'much' becomes 'big' (much means a big amount).
'ado' becomes 'bother' (both can mean trouble or fuss).
'about' is an insertion indicator.
'republican' becomes 'r' (abbreviation).
'bother' placed around 'r' is 'brother'.
'big'+'brother'='BIG BROTHER'
'as' acts as a link.
(Other definitions for big brother that I've seen before include "TV show - dictatorial leader" , "Orwell's head of state in "Nineteen Eighty-four"" , "1984's totalitarian controller -- TV reality show" , "A relatively large" , "oppressor, for Winston" .)