Exploited American Democrat following first of elections (4)
I believe the answer is:
'exploited' is the definition.
'american democrat following first of elections' is the wordplay.
'american' becomes 'us' (abbreviation for United States).
'democrat' becomes 'd'.
'following' means one lot of letters go next to another.
'first of elections' becomes 'e' (1st letter of 'elections').
'd' after 'e' is 'ed'.
(Other definitions for used that I've seen before include "no stranger" , "Old" , "Second hand" , "Second-hand - not wasted" , "Subject to exploitation" .)