The cunning strategy’s ending divine rule (8)
I believe the answer is:
thearchy
'divine rule' is the definition.
'the cunning strategy's ending' is the wordplay.
'cunning' becomes 'arch' (arch can mean cunning or tricksy).
'ending' indicates one should take the final letters (the ending of the word).
The final letter of 'strategy' is 'y'.
'the'+'arch'+'y'='THEARCHY'
(Other definitions for thearchy that I've seen before include "Rule by god(s)" , "Ecclesiastical governors" , "rulership" , "religious form of ruling" .)