Welcoming Democrat, cite changed ruling (5)
I believe the answer is:
edict
'ruling' is the definition.
(I have seen 'Authoritative ruling ' mean 'edict' so perhaps 'ruling' could also mean 'edict')
'welcoming democrat cite changed' is the wordplay.
'welcoming' is an insertion indicator (I've seen this in other clues).
'democrat' becomes 'd'.
'changed' indicates anagramming the letters.
'cite' anagrammed gives 'eict'.
'd' placed into 'eict' is 'EDICT'.
(Other definitions for edict that I've seen before include "Decree, order" , "Proclamation, law" , "Legally binding proclamation" , "Decree by authority" , "Declaration" .)