Here’s the answer copy-pasted:

I will bring an answer for question “How do we evaluate Stalin?” from Zhihu( Chinese Quora like webiste). This answer was finished two years ago. It got 6.2k up-votes.

Link:如何评价斯大林？ - 知乎

Here we go:

It is despicable to put aside historical background when evaluating a historical figure.

We now know much more information than the people living in the past, we should have a better understanding on what have happened.

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In January 1924, Lenin, the leader of Bolshevik passed away. Let’s take a look at what he left for Stalin:

1. Russian Empire dissolved, splitted into 6 pieces—Soviet Union,Finland, Poland,Estonia,Lithuania and Latvia. Among these new born countries

• Poland managed to get a large amount of territory which used to be a part of West Ukraine and West Belarus—-a large amount of territory of two later Soviet republics.
• Finland got Viborg area, an area Russia got in 1712 and Czar Alexander I partitioned to Finland for Finland as a part of Russian Empire.
• Romania got Bessarabia ,an area Russia empire annexed in 1829.

2. Despite new born Red army was able to win civil war, it was quite fragile when confronting against also new born Poland force. 700 thousand poorly armed army of Poland crushed Red army, forcing Soviet Union cede lands to Poland.
3. Russian economy was essentially backward. Continuous WWI,Civil War and War with Poland make it even worse. A famine hit Russia in 1921. Limited industrial capacity, especially military industry capacity collapsed basically.
4. All neighboring countries were hostile to Soviet Union except Mongolia. USA refuse to recognize Soviet Union. A Japanese invasion in far east was stopped not long ago.
5. Top leader of Soviet Communist party were mainly Jews, people with long term oversea experience, people with good education background or people who was born and raised in upper class family. Stalin, son of a shoemaker,ethnic minority from Georgia, who did not went to college was for sure an outsider. Being affected by ‘first lady’, Lenin left a will suggesting central committee of Soviet communist party to exempt Stalin as the General Secretary.
   Almost the entire Red army was under the command of Trotsky and Kamenev. Stalin had no friend in army expect a cavalry corp under the command of Budyonny and Voroshilov. Also, the army was full of his foe such as Tukhachevsky.

With the knowledge we know now, the task Stalin need to do was(Unlike video games, he would not know the exact content on what was required to be done):

1. In 1941, an army of 6 million troops led by Nazi Germany will Strike Soviet Union. This army just crushed UK-French allied force. In WWI, UK and French army were way better than Russian Empire army.
2. Before the incident above to occur, if Red army was not doing well against a probing attack from Japan, about 1 million Japanese army would swarming into Soviet Union far east territory.
3. Even if imperialist axis powers leading by Germany, Japan and Italy was defeated, imperialist group leading by USA and UK would remain hostile against Soviet Union. They will have atomic bomb technology by 1945.(Imperialist. Yes, that what Chinese would say about US, even today.)

When Stalin die, Soviet Union was like this:

1. Estonia,Lithuania and Latvia was a part of Soviet Union. Territory lost to Poland were all recaptured. Territory lost to Romania and Finland were all recaptured while forcing them to cede more. German and Hungry ceded part of their land to Soviet Union. Territory lost in Russo-Japanese war were all recaptured while occupied some Japanese land.
2. Nazi invading powers from Europe was completely crushed, red army occupied most of the Europe land to the east of Elbe River. Japanese army in Manchuria and Korean peninsula were all destroyed.
3. In the Soviet occupied part Germany, new established government follow command from Moscow. New established government in axis power or partially axis power countries like Czechoslovakia,Bulgaria,Romania and Hungry now follow command from Moscow. Poland and north Korea which was liberated by Soviet Union established government which follow command from Soviet Union. Communist in China and Albania received help from Soviet Union, resulting new pro-Soviet government of these countries to be established. Pro-soviet government in North Vietnam was about to born.
4. In terms of industrial power, Soviet Union was NO.1 in Europe and NO.2 in the world. It can produce atomic bomb. Hydrogen bomb and nuclear power plant was about to be built.

Now, let’s start a conversion. If you are Stalin, can you do better?