Alarm with Kew becoming wild -- who makes the rules? (8)
I believe the answer is:
lawmaker
'who makes the rules?' is the definition.
(lawmakers make new rules)
'alarm with kew becoming wild' is the wordplay.
'with' is a charade indicator (letters next to each other).
'becoming wild' is an anagram indicator.
'alarm'+'kew'='alarmkew'
'alarmkew' with letters rearranged gives 'LAWMAKER'.
(Other definitions for lawmaker that I've seen before include "sitting in Parliament?" , "Sod, possibly" , "Legislator" .)