Remains inclined towards socialism concerning onset of strikes
I believe the answer is:
leftovers
'remains' is the definition.
(thesaurus)
'inclined towards socialism concerning onset of strikes' is the wordplay.
'inclined towards socialism' becomes 'left' (I've seen this before).
'concerning' becomes 'over' (I've seen this before).
'onset of' indicates taking the first letters.
The initial letter of 'strikes' is 's'.
'left'+'over'+'s'='LEFTOVERS'
(Other definitions for leftovers that I've seen before include "survivors" , "Remains" , "Uneaten scraps" .)