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 quite see how this works, but
'old' could be 'o' (abbreviation) and 'o' is found in the answer.
'marines' could be 'rm' (abbreviation for 'Royal Marines') and 'rm' is present in the answer.
an anagram of 'protestor' is 'sttrooper' which is located in the remaining letters.
No letters remain.
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" .)