Extradition possibly helping to secure nasty pirate (12)
I believe the answer is:
repatriation
'extradition' is the definition.
(thesaurus)
'helping to secure nasty pirate' is the wordplay.
'helping' becomes 'ration' (a ration is a serving or helping).
'to secure' is an insertion indicator (inserted letters are secured inside).
'nasty' indicates anagramming the letters (a nasty or wrong spelling).
'pirate' with letters rearranged gives 'epatri'.
'ration' going around 'epatri' is 'REPATRIATION'.
'possibly' acts as a link.
(Other definitions for repatriation that I've seen before include "Sending home" , "The returning of someone to their own country" .)