As the period of détente during the 1970’s continued, the rapprochement between the Soviet Union and the United States seemed to intensify and promised to lessen tensions between the rival countries. The invasion of Afghanistan and the imposition of a communist regime seemed to signal that the communists had not abandoned their dream of global conquest. This caused the United States to renew their efforts to halt the communist expansion by supporting the Afghan rebels in their efforts to expel the Russians.
After the Soviet invasion, progress towards furthering friendly relations between the west and Soviets halted and even moved backwards. Ronald Reagan, the newly elected American president increased assisted to the Afghan rebels in 1981 and assumed a much more confrontational stance in dealings with the Soviets. In response to the American attitude, Soviet attitudes to the west hardened as well. The Soviets also increased their efforts to pacify Afghanistan in order to avoid losing face to the rest of the world.
As the cold war heated back up after the invasion of Afghanistan, both sides engaged in a series of tit-for-tat escalations of tensions. The Soviets emplaced intermediate range ballistic missiles (IRBM) in eastern Europe and the United States responded by deploying its own IRBM systems in West Germany. President Reagan increased US defense spending in an effort to force the Soviets to do the same, which they had to do if they wanted to maintain the balance of power in Europe. In the meantime, the war in Afghanistan dragged on inconclusively for the Soviets.
The increased Soviet defense spending and the war in Afghanistan combined with a moribund economy forced the Soviets to make difficult decisions. Mikhail Gorbachev attempted to reform the Soviet economy, but discovered that you cannot give people a little bit of freedom and starting in 1989 the Warsaw Pact nation’s spurned communism in a series of peaceful revolutions. Starting in 1987 with the signing of the IRBM treaty with Washington the Soviets tempered their positions in the face of continued US confrontation. In 1989, the Soviets acknowledged they could not win in Afghanistan and withdrew their military from the country. In 1991, the Soviet regime collapsed due to the dual pressure of political reformists and the terrible economy occasioned by the attempt to match US defense expenditures.
Ultimately, the Afghan invasion and the renewed confrontation with the west it caused led to the fall of communism in not only Russia but throughout Europe. The communist regime was unable to compete with the economic power of the west and in fact became increasingly dependent on western loans in order to stay in power. Communism proved itself a failed model and the renewed cold war strained the communist system more than it could take. Communism was probably doomed anyway; the Afghan invasion and its consequences only sped up the collapse.