As crazy monarch, I'll ban a president (7,7)
I believe the answer is:
abraham lincoln
'president' is the definition.
(Abraham (Abe) Lincoln)
'as crazy monarch i'll ban a' is the wordplay.
'as crazy' indicates anagramming the letters (I've seen this in other clues).
'monarch'+'ill'+'ban'+'a'='monarchillbana'
'monarchillbana' is an anagram of 'ABRAHAM LINCOLN'.
(Other definitions for abraham lincoln that I've seen before include "fatally, he watched some play" , "president" , "Famous American" .)