Crossword Genius

American marines sent here lack preparation (12)

Ross

I believe the answer is:

leathernecks

'american marines' is the definition.
(informal term for the United States Marines)

'sent here lack preparation' is the wordplay.
'preparation' indicates anagramming the letters.
'sent'+'here'+'lack'='sentherelack'
'sentherelack' is an anagram of 'LEATHERNECKS'.

I've seen this clue in The Guardian.
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