Compare and contrast Stalin's Soviet Union with Hitler's Germany.
Both regimes were totalitarian. This means that the state controlled all aspects of life. The Nazi state in Germany and the Communist state in the Soviet Union told their citizens what to do, where to live, where to work, and even how to think. There was no civil society to speak of. The Nazis were particularly ruthless and effective at getting rid of any group or organization that could vaguely have constituted an independent source of power, whether they were labor unions, social clubs, or youth organizations.
At the apex of the Nazi Party and the Communist Party of the Soviet Union stood the unchallenged leadership of one man—Adolf Hitler and Josef Stalin, respectively. Both dictators insisted on the absolute loyalty and submission of their subordinates. However, there were slight differences in their respective methods of leadership. In Nazi Germany, if you stayed loyal to the Fuhrer, then the likelihood was that you were safe.
In the Soviet Union, on the other hand, Stalin routinely executed members of the Party and government without any obvious reason. Party members and officials found themselves caught in a bind. If they didn't show sufficient loyalty to Stalin, they could end up being suspected as traitors; yet, even if they were fanatically loyal, they could still easily fall out of favor, either because Stalin perceived them as a threat to his power, or because they were caught on the hop by a sudden change in policy, such as what happened when the collectivization of agriculture was slowed down.
Terror was the chief method of consolidating power in the two dictatorships. Nazi terror tended to be more methodical, carefully targeted at certain groups such as Jews, Communists, and Social Democrats. Under Stalin, however, it seemed that virtually no one was safe. It didn't matter who or what you were, a knock at the door in the middle of the night could herald a one-way trip to a Siberian labor camp or some dank, dingy basement with soundproofed walls. Even the wife of Foreign Minister Molotov, one of the most important men in the state, ended up in the gulag. But there was some method to Stalin's madness. If no one, no matter how important, could feel safe, then they'd be too busy looking out for themselves to think about toppling Stalin from power.
In all societies, whatever the system of government, things regularly go wrong. In totalitarian states, however, the government can never admit that it's responsible for any problems. The Nazis, for example, developed a cult of personality around Hitler. State propaganda portrayed him as some kind of demigod, a towering genius who could do no wrong. So when something did go wrong, there had to be another explanation. Nazi propaganda came up with a handy list of scapegoats, upon whom all of Germany's ills could be blamed. The most common of these were, of course, the Jews.
A similar list was drawn up in the Soviet Union to account for the numerous failures of state policy, especially in regard to collectivization and mass industrialization. Propaganda gave the impression that there were wreckers and saboteurs hiding in every factory, every collective farm and every workplace, just waiting to do whatever they could to destroy the Communist system. The collectivization of agriculture had led to famine and chronic food shortages on a massive scale. Yet the official line was that Stalin, The Great Helmsman himself, could not be in any way responsible for such horrors; the problem had to be with kulaks, or rich peasants, shamefully hoarding their grain in order to starve the workers and undermine the great proletarian revolution.
Many of the methods and forms used by Stalin and Hitler were quite similar. Both men employed propaganda and terror to gain and maintain power, though Hitler tended to utilize speeches, both public, and on the radio, than Stalin did. Both engineered bloody purges of party members, including many that had been instrumental in their rise to power. Both employed secret police to tamp down dissent, which was punished harshly, often with incarceration in forced labor camps. Both, additionally, maintained a single-party state.
Many of the differences between the two were ideological, though ideology frequently bled into policy. Hitler nationalized some industries, but the sort of collectivization project embarked upon by Stalin was not part of his program. Additionally, the ideological foundations of Hitler's regime were based upon ultranationalism and a racist vision of the German state; Stalin's on the overthrow of capitalism.