Element of vote the right must secure (6)
I believe the answer is:
tether
'secure' is the definition.
(thesaurus)
'element of vote the right must' is the wordplay.
'element of' indicates the answer is hidden within the clue (I've seen this in other clues).
'TETHER' is hidden within 'vote the right must'.
(Other definitions for tether that I've seen before include "restricts movement" , "Rope for confining animal" , "Tie up with a rope, an animal perhaps" , "restrain boxers, say" , "Rope for tying animal" .)