Firm with politician within the law, but sharing guilt (9)
I believe the answer is:
complicit
'sharing guilt' is the definition.
(I've seen this before)
'firm with politician within the law' is the wordplay.
'firm' becomes 'co' (a firm is a company).
'with' is a charade indicator (letters next to each other).
'politician' becomes 'mp'.
'within the law' becomes 'licit' (I've seen this before).
'co'+'mp'+'licit'='COMPLICIT'
'but' acts as a link.
(Other definitions for complicit that I've seen before include "guilty with others?" , "Sharing guilt" , "Being party to a crime" , "Conniving" , "Involved with others in illegality" .)