Question

In 1991 the Soviet Union collapsed MAINLY because

Answer 1

...of Gorbachev. At least that's what I'd probably say. I don't know what choices you might have to answer that and I know it sounds like a weird thing to say, but here's why.

Gorbachev wanted to reform the Soviet Union and had a lot of good ideas on how to do it. At the time, their economy was on the verge of disaster - the US was literally spending them to death with the arms race. He also wanted to slowly loosen restrictions in order to try and encourage ideas on how to improve everyone's lives in the country without fear of being censored. Glasnost was the idea of "openness" while perestroika was aimed at making the bureaucracy more transparent.

Now, Gorbachev was a good guy -- he really wanted to improve lives within the Soviet Union. The problem was that the changes he created snowballed into something even he couldn't stop from happening.

Meanwhile, other events in Eastern Europe were challenging Soviet control and influence from the fall of the Berlin Wall to the Baltic republics seeking greater independence. All of these ate away at the USSR.

Gorbachev's policies had also sparked an explosion of criticism within the country now that people were freer to express what they thought and avalanched into calls for greater democracy and choice, eventually forcing the Party to give up power. Gorbachev had great intentions, but dissolving the USSR wasn't what he wanted -- he only wanted to modernize and slowly democratize the system, not completely tear it down.