Right to vote on his admittance to European state (9)
I believe the answer is:
franchise
'right to vote' is the definition.
(synonyms)
'his admittance to european state' is the wordplay.
I cannot really see how this works, but
'european' could be 'e' (abbreviation e.g. EU) and 'e' is located in the answer.
'state' could be 'hi' (abbreviation for Hawaii) and 'hi' is present in the answer.
The remaining letters 'francs' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'on' acts as a link.
Can you help me to learn more?
(Other definitions for franchise that I've seen before include "Dealership" , "Authorisation to sell a company's goods or services in a specified area" , "For citizen, right" , "rights of citizenship" , "The right to vote in a parliamentary election." .)