Judge slightly occupied by Republican charge (9)
I believe the answer is:
arbitrate
'judge' is the definition.
(to arbitrate is to judge or decide)
'slightly occupied by republican charge' is the wordplay.
'slightly' becomes 'a bit' ('a bit' can mean 'slightly' or 'somewhat').
'occupied by' means one lot of letters goes inside another (inserted letters occupy or enter the word).
'republican' becomes 'R' (political abbreviation).
'charge' becomes 'rate' (rate is a kind of charge).
'abit' placed around 'r' is 'arbit'.
'arbit'+'rate'='ARBITRATE'
(Other definitions for arbitrate that I've seen before include "Decide" , "judge" , "Help settle a dispute" , "Act between disputing parties" , "Mediate" .)