Yalta Conference attendee (6)
I believe the answer is:
'yalta conference attendee' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for stalin that I've seen before include "Dreaded dictator among Latins" , "Joseph -, Russian World War two dictator" , "Communist dictator" , "Mass-murderer" , "Former USSR leader" .)