Decree from nation's leader after radio broadcast (6)
I believe the answer is:
ordain
'decree' is the definition.
(I know that ordain is a more specific form of decree)
'nation's leader after radio broadcast' is the wordplay.
'leader' suggests taking the first letters.
'after' is a charade indicator (letters next to each other).
'broadcast' indicates anagramming the letters (letters scattered or cast around).
The initial letter of 'nation' is 'n'.
'radio' anagrammed gives 'ordai'.
'n' after 'ordai' is 'ORDAIN'.
'from' is the link.
(Other definitions for ordain that I've seen before include "Initiate as priest" , "Lay down (law)" , "Make a decree" , "Decree or consecrate" , "Appoint as priest" .)