Migrant protestor catches old marines assaulting Nazi (5,7)
I believe the answer is:
storm trooper
'nazi' is the definition.
(storm trooper is a kind of nazi)
'migrant protestor catches old marines assaulting' is the wordplay.
I cannot really understand how this works, but
'old' could be 'o' (abbreviation) and 'o' is found within the answer.
'marines' could be 'rm' (abbreviation for 'Royal Marines') and 'rm' is found within the answer.
an anagram of 'protestor' is 'sttrooper' which is present in the left over letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for storm trooper that I've seen before include "Nazi Brownshirt" , "Assault soldier" , "Soldier trained to attack suddenly" .)