Both Hitler and Mussolini had the ambition of expanding their countries, which was the cause of the alliance of the two countries. However, Italy was more like Germany's puppet that followed Germany's (more like Hitler's) will. Both leaders set up dictatorships and was popular among the masses of their countries. Stalin on the other hand, was also into the expansion of Russia by the means of expanding into the Soviet Union. All three were known for the usage of secret police in order to keep themselves in power. Both Stalin and Hitler set up camps in order to exterminate thousands if not millions of people.
All of them were totalitarian leaders (totalitarian leaders- control all or most aspect of citizens lives) I know that both stalin and mussolini used police spies Stalin rules after lenin, lauches the great purge ( campain to anyone threatening his power ) Both Hitler and Stalin have labor camps Mussolini formed facist party All put strict censorship, government cortrol over the media and used propaganda
