Voting system about right, is one captive? (8)
I believe the answer is:
prisoner
'captive?' is the definition.
('prisoner' can be a synonym of 'captive')
'voting system about right is one' is the wordplay.
'voting system' becomes 'pr' (I've seen this in other clues).
'about' is an insertion indicator.
'right' becomes 'r' (common abbreviation).
'r'+'is'+'one'='risone'
'pr' enclosing 'risone' is 'PRISONER'.
(Other definitions for prisoner that I've seen before include "Condemned" , "Person behind bars" , "Captive, incarcerated criminal" , "One kept confined" , "Hostage" .)