Soviet Union, as we all know, was a major player in the Cold War, and sought every advantage it could get over its United States counterpart. The Soviet Union decided it would be best to expand its influence into the state known as Afghanistan. The alliance between the Soviet Union and Afghanistan began with Afghanistan’s call for aid to the Soviet Union against the constant invading imperialistic forces (TASS). One radio recording even states the official call of the Afghan government calling for all kinds of aid in hopes of protecting their borders and by honoring the “1978 Treaty of Friendship” agreement between the two countries (Pravda).
http://www.history.com/this-day-in-history/ussr-and-afghanistan-sign-friendship-treaty
This source listed above gives a great description of what the 1978 Treat of Friendship is, what it entails, and how it came to be.
The Soviet Union agreed and sent a small battalion, meant only to act as a buffer against invading external forces. Their actions were justified by the “1978 Treaty of Friendship,” meant to help protect its neighbors and build alliances with the country of Afghanistan (TASS). As the current leader of the country was executed and replaced, the Soviets placed Babrak Karmal, who assassinated and replaced the Afghani leader Nur Mohammad Taraki. However, it was clear that the Soviet Party within Afghanistan faced heavy resistance from the Islamic population, and was in fact splintering into many other groups at the time.
The Islamic fighters that we have all learned about, the Mujaheddin, fought guerrilla style warfare against the Soviet troops since they were no match in open combat. The mountainous terrain made for a good ally in the fighting against the Soviet forces. Once the Mujahideen crossed into Pakistan and united their forces, the Afghanistan War in a since began, as the Mujahideen fought against the Soviet backed Afghan forces for many years, eventually ending in Soviet withdrawal due to a huge monetary cost of the conflict on the sickly Russian economy.
This picture depicts the various forces that made up the Mujahideen. As mentioned earlier, the Mujahideen were the fighters united against the Soviet backed Afghan forces, and wanted to repel any Soviet advances through guerrilla warfare. Their constant incursions forced the Soviet Union to evacuate their forces from the country for being too costly.
Another reason why the Soviet Union was forced to pull out was due to the Stinger Missiles given to the Mujahideen forces. With these weapons, the Mujahideen fighters began to shoot down many Soviet war helicopters, each one being destroyed dealing a major blow to the Soviet treasury (they were quite expensive and many were shot down).
This picture depicts the Soviet forces withdrawing from the country of Afghanistan. As the resistance forces rose and continuously caused more and more damage to the Soviet forces, the Soviet leaders were forced to pull out, as the conflict was becoming a costly money-pit to the already weakened Soviet economy.
After the withdrawal of Soviet troops, the Soviet Union had to defend itself and its actions, which were contested by western sources saying they were not honoring their agreement of leaving Afghanistan. The Soviet Union withdrew 50% of its armed forces within the first three months of the signing of the Geneva Accords for Afghanistan. Also, the Soviet forces still positioned were faced with constant attacks from splinter organizations and resistance fighters, meaning the Russian forces had to adapt to a self defense style of protection for themselves (Current Digest of the Russian Press). The Soviet command stated that the forces still positioned after the Afghan war were meant to deter any future conflicts of such nature and to provide protection for the civilian population.
Sources:
http://dlib.eastview.com.ezproxy.lib.vt.edu/browse/doc/13609051
Farm2.static.flickr.com/1059/536686318_63e7733345.jpg
Foreign Broadcast Information Service, Daily Report (28 and 31 December 1979), D3, D5 & D7, D11.
http://www.history.com/this-day-in-history/ussr-and-afghanistan-sign-friendship-treaty
Pravda, 29 December 1979