Compare Liberal with President Clinton, ultimately (5)
I believe the answer is:
liken
'compare' is the definition.
('liken' can be a synonym of 'compare')
'liberal with president clinton ultimately' is the wordplay.
'liberal' becomes 'l' (abbreviation).
'with' says to put letters next to each other.
'president' becomes 'ike' (I've seen this before**).
'ultimately' suggests the final letters.
The last letter of 'clinton' is 'n'.
'l'+'ike'+'n'='LIKEN'
(Other definitions for liken that I've seen before include "Point out the resemblance (to)" , "Equate" , "Represent as similar" , "Compare" .)