Old president - because of sole voter (9)

I believe the answer is:

roosevelt

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'old president' is the definition.
(Theodore Roosevelt or Franklin Delano Roosevelt)

'of sole voter' is the wordplay.
'of' is an anagram indicator (the answer comes from or 'of' the letters).
'sole'+'voter'='solevoter'
'solevoter' with letters rearranged gives 'ROOSEVELT'.

'because' is the link.
This may not be correct. It may be part of another bit of the clue.

Can you help me to learn more?

(Other definitions for roosevelt that I've seen before include "Name of two twentieth century US presidents" , "Teddy" , "Surname of 26th and 32nd US presidents" , "See president" , "former president" .)

I've seen this clue in the Sydney Morning Herald.

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