Killer, idiot repeatedly elected (8)
I believe the answer is:
assassin
'killer' is the definition.
(I know that killer can be written as assassin)
'idiot repeatedly elected' is the wordplay.
'idiot' becomes 'ass' (I've seen this in another clue).
'repeatedly' indicates the doubling of some letters.
'elected' becomes 'in' (in government).
'ass' doubled is 'assass'.
'assass'+'in'='ASSASSIN'
(Other definitions for assassin that I've seen before include "Killer of prominent figure" , "Murderer (of prominent figure)" , "One making hits" , "Killer of prominent person" , "Carlos the Jackal was one" .)