@[u]Brendan Rizzo:
The U.S.S.R. was going well with the communist agenda, until traitor Stalin took power. He was never a socialist, nor a communist. He was a fascist in a Red disguise. The ultimate traitor who accused the remaining bolscheviks of treason, killing them (after him, only Mikoyán, Mólotov and Stalin himself were the remaining bolscheviks still alive after the purges), and using socialism, communism and Lennin's image for an excuse to gain wealth and benefits at the expense of the working class.
You seem to be falling into the mistake many have been falling. Stalinist USSR was not socialist nor communist, but a bureaucratized and degenerate workers' state, a non-capitalist state in which the operation was controlled by a ruling caste (who was not a social class nor an ethnic group, A.K.A. Stalin and friends). After Stalin's death, the U.S.S.R. was never the same. It was de-Stalinized, of course, but it was still ruled by bureaucrats and not by the people itself. As an example, here's a quote from Gorbachev:
"There is now much discussion about the role of Stalin in our history. His was an extremely contradictory personality. To remain faithful to historical truth we have to see both Stalin's incontestable contribution to the struggle for socialism, to the defense of its gains; the gross political errors, and the abuses committed by him and by those around him, for which our people paid a heavy price and which had grave consequences for the life of our society."
Gorbachev was prepared to accept that Stalin committed crimes. But the emphasis is on his positive achievements.
For me the Soviet Union ceased to exist since 1924.