Character in political group falling short (4)
I believe the answer is:
part
'character' is the definition.
('part' can be a synonym of 'character')
'political group falling short' is the wordplay.
'political group' becomes 'party' (I've seen this before).
'falling short' means to remove the last letter.
'party' with its last letter taken away is 'PART'.
'in' is the link.
(Other definitions for part that I've seen before include "unemployed actor hopes for" , "Portion of a whole" , "Divide; role" , "Sever; portion" , "Some; break" .)