Heralds start to proclaim new decrees (8)
I believe the answer is:
precedes
'heralds' is the definition.
(I've seen this before)
'start to proclaim new decrees' is the wordplay.
'start to' suggests taking the first letters.
'new' indicates an anagram.
The initial letter of 'proclaim' is 'p'.
'decrees' anagrammed gives 'recedes'.
'p'+'recedes'='PRECEDES'
(Other definitions for precedes that I've seen before include "Heralds" , "Comes before" , "Goes before in time or order" , "Goes in front (of)" , "has priority" .)