The timeline of the collapse of the Soviet Union can be traced to September 13, 1985. On this date, Sheikh Ahmed Zaki Yamani, the minister of oil of Saudi Arabia, declared that the monarchy had decided to alter its oil policy radically. The Saudis stopped protecting oil prices, and Saudi Arabia quickly regained its share in the world market. During the next six months, oil production in Saudi Arabia increased fourfold, while oil prices collapsed by approximately the same amount in real terms.
As a result, the Soviet Union lost approximately $20 billion per year, money without which the country simply could not survive. The Soviet leadership was confronted with a difficult decision on how to adjust. There were three options--or a combination of three options--available to the Soviet leadership.
First, dissolve the Eastern European empire and effectively stop barter trade in oil and gas with the Socialist bloc countries, and start charging hard currency for the hydrocarbons. This choice, however, involved convincing the Soviet leadership in 1985 to negate completely the results of World War II. In reality, the leader who proposed this idea at the CPSU Central Committee meeting at that time risked losing his position as general secretary.
Second, drastically reduce Soviet food imports by $20 billion, the amount the Soviet Union lost when oil prices collapsed. But in practical terms, this option meant the introduction of food rationing at rates similar to those used during World War II. The Soviet leadership understood the consequences: the Soviet system would not survive for even one month. This idea was never seriously discussed.
Third, implement radical cuts in the military-industrial complex. With this option, however, the Soviet leadership risked serious conflict with regional and industrial elites, since a large number of Soviet cities depended solely on the military-industrial complex. This choice was also never seriously considered.
Unable to realize any of the above solutions, the Soviet leadership decided to adopt a policy of effectively disregarding the problem in hopes that it would somehow wither away. Instead of implementing actual reforms, the Soviet Union started to borrow money from abroad while its international credit rating was still strong. It borrowed heavily from 1985 to 1988, but in 1989 the Soviet economy stalled completely.