More than enough beer to keep person who's been elected (5)
I believe the answer is:
ample
'more than enough' is the definition.
(I've seen this before)
'beer to keep person who's been elected' is the wordplay.
'beer' becomes 'ale' (type of beer).
'to keep' means one lot of letters goes inside another.
'person who's been elected' becomes 'MP' (Member of Parliament).
'ale' placed around 'mp' is 'AMPLE'.
(Other definitions for ample that I've seen before include "No more, please!" , "Easily sufficient" , "Generous" , "Large, capacious" , "Sealed glass container for dose of medicine" .)