Kagan appointer (5)
I believe the answer is:
obama
'kagan appointer' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for obama that I've seen before include "Trump's predecessor" , "US president born in Hawaii" , "44th US President" , "President awarded the 2009 Nobel Peace Prize" , "one with top job in Washington" .)