Leader in power, citizen (9)
I believe the answer is:
president
'leader' is the definition.
(I know that President is a type of politico)
'power citizen' is the wordplay.
'power' becomes 'p'.
'citizen' becomes 'resident' (I've seen this before).
'p'+'resident'='PRESIDENT'
'in' acts as a link.
(Other definitions for president that I've seen before include "Country's leader" , "The elected head of a republic" , "Leader of a republic" , "Head of a republic - or a club" , "American leader" .)