Country centrally engaged in crusade (7)

I believe the answer is:

america

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'country' is the definition.
(United States of America)

'centrally engaged in crusade' is the wordplay.
'centrally' indicates the central letters.
'engaged' becomes 'became rigid' (becoming rigid is a kind of engaging).
'in crusade' becomes 'ca' (I am not sure about this - if you are sure you should believe this answer much more).
The central letters of 'becamerigid' are 'ameri'.
'ameri'+'ca'='AMERICA'

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(Other definitions for america that I've seen before include "country targeted by 3 [ROMNEY]" , "Ira came from the continent" , "Camera I found in the continent" , "North or South, it's a continent" , "Continent named after Vespucci" .)

I've seen this clue in The Guardian.

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