Mr Gore relies on retaining current benefactors (9)
I believe the answer is:
altruists
'benefactors' is the definition.
(altruist is a kind of benefactor)
'mr gore relies on retaining current' is the wordplay.
'mr gore' becomes 'Al' (US politician Al Gore).
'relies on' becomes 'trusts' (I've seen this in another clue).
'retaining' indicates putting letters inside (inserted letters are held or retained).
'current' becomes 'I' (symbol for electric current).
'trusts' going around 'i' is 'truists'.
'al'+'truists'='ALTRUISTS'
(Another definition for altruists that I've seen is " Philanthropists".)