Utilitarian half of Reagan's agenda (7)
I believe the answer is:
realist
'utilitarian' is the definition.
(thesaurus)
'half of reagan's agenda' is the wordplay.
'half of' means to take half the letters.
'agenda' becomes 'list' (I've seen this in another clue).
'reagan' with half the letters taken is 'rea'.
'rea'+'list'='REALIST'
(Other definitions for realist that I've seen before include "Someone who's pragmatic" , "Pragmatist" , "One's practically inclined" , "Writer like Balzac" , "no Walter Mitty?" .)