Conspire internationally to retain control (4)
I believe the answer is:
rein
'control' is the definition.
(rein is a kind of control)
'conspire internationally to retain' is the wordplay.
'to retain' says the answer is hidden in the clue (I've seen 'retaining' mean this).
'REIN' is hidden within 'conspire internationally'.
(Other definitions for rein that I've seen before include "kidney?" , "Curb" , "Harness item" , "one's attached to a bit" , "Part of a horses's harness" .)