Inevitable consequences of article in prominent feature on war? (5,8)
I believe the answer is:
chain reaction
'inevitable consequences' is the definition.
(a chain reaction is a series of consequences)
'article in prominent feature on war?' is the wordplay.
'article' becomes 'a' (the indefinite article in English).
'in' means one lot of letters goes inside another.
'prominent feature' becomes 'chin' (facial feature).
'on' becomes 're' (regarding).
'war?' becomes 'action' (action can mean action in war).
'a' inserted into 'chin' is 'chain'.
'chain'+'re'+'action'='CHAIN REACTION'
'of' acts as a link.
(Other definitions for chain reaction that I've seen before include "Diana Ross song" , "Self-maintaining process" , "Sequence" , "Series of consequences" , "This process should continue" .)