Franchise that can cause us very loud vehemence (8)
I believe the answer is:
suffrage
'franchise that' is the definition.
'suffrage' can be an answer for 'franchise' (synonyms). I'm not certain of the remainder of the definition.
'us very loud vehemence' is the wordplay.
'us' becomes 'su' (I can't explain this - if you can you should give a lot more credence to this answer).
'very loud' becomes 'ff' (musical abbreviation).
'vehemence' becomes 'rage' (I've seen this in another clue).
'su'+'ff'+'rage'='SUFFRAGE'
'can cause' acts as a link.
Can you help me to learn more?
(Other definitions for suffrage that I've seen before include "The right to vote in political elections" , "The right to vote, as won by women" .)