Doubt it's right Iran vetoes resolution (11)
I believe the answer is:
reservation
'doubt' is the definition.
(reservation is a kind of doubt)
'right iran vetoes resolution' is the wordplay.
'right' becomes 'r' (common abbreviation).
'resolution' indicates anagramming the letters.
'iran'+'vetoes'='iranvetoes'
'iranvetoes' anagrammed gives 'eservation'.
'r'+'eservation'='RESERVATION'
'it's' is the link.
(Other definitions for reservation that I've seen before include "Expression of doubt; table booking" , "Putting aside" , "Qualification, proviso" , "Booking - qualification" , "Booking (in a restaurant)" .)