Re: In 1991, 90% of the Ukraine population voted for independence from Russia...
This doesn't make sense. Ukraine was a part of the Soviet Union, which included 13 other republics, besides Ukraine and Russia.
Ukraine did not and could not vote for independence from Russia, because it wasn't a part of Russia.
The Soviet Union itself fell apart as a result of Russia declaring independence from the USSR.
Basically, there was a coup attempt against Gorbachev. Yeltsin, who was the head of the Russian Republic, took over Kremlin and the Soviet government. He didn't have any authority to rule the country. The heads of the 14 other republics weren't going to recognize his rule. And that's why the whole country fell apart.
They literally didn't have any central government anymore, after Yeltsin took over Kremlin and arrested the Politburo members. Yeltsin wasn't going to give up his control of Moscow and Russia. And that's why the whole country fell apart.