King stops US state soldier (6)
I believe the answer is:
marine
'soldier' is the definition.
(I know that marine is a type of soldier)
'king stops us state' is the wordplay.
I cannot quite understand how this works, but
'king' could be 'r' (abbreviation for rex, king in Latin) and 'r' is found in the answer.
'state' could be 'maine' (US state) and 'maine' is located in the leftover letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for marine that I've seen before include "Relating to the sea" , "Soldier serving on land and sea" , "Sea-soldier" , "Airmen (anag.)" , "jolly" .)