Fair enough, I would imagine that the only way that Stalin's life would have ended was with a bomb then no?
Was this a possibility? in a "what if" anything is possible
Was it probable? probably not... This would all depend on whether an Atomic bomb would have been dropped on Moscow and if Stalin was present. What might the chances of Stalin being present at Moscow knowing fully well that war with the Allies would make Moscow the primary target with such a weapon as the one which was used on Japan? Not mention it ever reaching the capital?
Also how long might it take to find out as to what Stalin really did? After all its been over 50 years and we still dont know everything, surely all wouldnt have been unraveled in a year or so.... Communism was afterall was still alive in Russia. And who is to say that the same leaders would not have taken place after Stalin's death..
Going this route just seems leave too many variables open. What if a soviet agent poisoned Truman? what then?