Struggling marines succeeded in close call (4,4)
I believe the answer is:
near miss
'close call' is the definition.
(I've seen this before)
'struggling marines succeeded in' is the wordplay.
'struggling' indicates an anagram (I've seen this in other clues).
'succeeded' becomes 's' (genealogical abbreviation).
'in' indicates putting letters inside.
'marines' with letters rearranged gives 'nearmis'.
'nearmis' placed around 's' is 'NEAR MISS'.
(Other definitions for near miss that I've seen before include "Close call" , "that doesn't quite hit the target" , "Wide of the target in seminars" , "Not a direct hit, but very close" , "A narrowly avoided collision in seminars" .)