Destructive policy: a pact must be arranged (11)
I believe the answer is:
apocalyptic
'arranged' is the definition.
Both the definition and answer are adjectives. Maybe there's an association between them I don't understand?
'destructive policy a pact' is the wordplay.
'destructive' indicates an anagram (I've seen this in other clues).
'policy'+'a'+'pact'='policyapact'
'policyapact' is an anagram of 'APOCALYPTIC'.
'must be' acts as a link.
Can you help me to learn more?
(Other definitions for apocalyptic that I've seen before include "disastrous" , "threatening disaster" , "Momentous, catastrophic" .)