The fall of the Soviet Union was a monumental event in human history. The sudden collapse of Communism changed the course of history forever. The events that led to the dissolution of the USSR are mostly blamed on Mikhail Gorbachev. In the long run, the collapse was more or less inevitable. It was the slow changes of the 1950s that created Gorbachev in the first place.
Factors Behind the USSR Collapse
The period from 1964-1982, when Leonid Brezhnev was the leader of USSR, is known as ‘The Stagnation’. This ‘stagnation’ later became the basis of a new revolution. Brezhnev retained the economic and political freedoms granted by Khrushchev in the 1950s. This resulted in rapid urbanisation and the creation of a new middle class. The middle class, as we know, is closely associated with the emergence of democracy and nationalism. In this way, Brezhnev was preparing the way for the fall of his country.
The failures of Communism as a system were also becoming more and more apparent. The enthusiasm of the Revolution was fading away. Meanwhile, the economy continued to slow down fast. The annual growth rate of GDP was about 7 % in the late-1960s. It fell to only 3 % by the 1980s.
Fall of the Soviet Union
In 1985, the USSR was by far the largest country in the world. Furthermore, it also presided over a large bloc of Socialist allies in Eastern Europe. One year after the reform-minded Mikhail Gorbachev took office, however, the Chernobyl incident laid bare all the deficiencies of the Soviet bureaucracy. The result was a complete overhaul of the entire system. Although he failed to recover the economy, Gorbachev’s allowed the nationalists to have their voice heard for the first time. This was the policy of glasnost (“Transparency”).
Add to this the fact that Gorbachev ended the policy of Brezhnev Doctrine. It was under this doctrine that the USSR had preserved the Eastern Bloc so far with direct interventionism. This time, Gorbachev did not crush the protests for democracy in Poland, East Germany and other Communist nations in 1989.
Starting with the Baltic States in March 1990, republics within the Soviet Union also started declaring independence. Moscow still did not respond with a violent invasion. A last coup to overthrow Gorbachev failed in August 1991. Gorbachev himself resigned in the last week of December, marking the end of an era.
 Fainberg, Dina & Artemy M. Kalinovsky (ed.), “Reconsidering Stagnation in the Brezhnev Era: Ideology and Exchange” (2016, Lanham, Maryland: Lexington Books).
 Sakwa, Richard, “The Rise and Fall of the Soviet Union 1917-1991 (1999, New York City, New York: Routledge), pp. 412-413.
 For a survey of how Gorbachev specifically contributed to the fall of the USSR, see: Smith, Jeremy, “The Fall of Soviet Communism 1985-91” (2005, London, United Kingdom: Macmillan).