Veto such as accepted by state (8)
I believe the answer is:
negation
'veto' is the definition.
(a veto negates or cancels something)
'as accepted by state' is the wordplay.
'as' becomes 'eg' (I've seen this in other clues).
'accepted by' is an insertion indicator.
'state' becomes 'nation' (synonyms).
'eg' placed inside 'nation' is 'NEGATION'.
'such' is the link.
(Other definitions for negation that I've seen before include "Making denial" , "opposite" , "disagreement" , "Contradiction" , "Cancellation" .)