Successful in what regard? Stalin ended up dying of natural causes, Russia and Ukraine transformed from a backwards agrarian economy to a despotic industrial economy, the Soviet Army took a good chunk of Europe during WWII, the Soviet Union became a superpower, and during his rule it could be argued that the Soviet bureaucracy was incredibly efficient. I don't actually think we should take Stalin as a role-model for how to run a government (I was being tongue-in-cheek in my above comment) but it is amazing what you can accomplish when you have a total disregard for human rights, all of the levers of the State, a ruthless secret police, and an enormous amount of natural resources.