Mixture leaning toward Stalin-after all he approved Kim Il Sung's invasion of South Korea, even if that was apparently a difficult decision for Stalin.
By the time the Korean War drew to a close. Stalin and Truman had passed from the scene, but not without instituting the East/West division and its symptoms (Eastern Bloc, Red Scare, H-Bomb, etc) as geopolitical realities.
Absent that war, USA v. USSR would most likely have been merely the latest chapter in great power contretemps amidst a (seemingly) entropic world.