Vietnamese Military Intervention Transformed into Khmer Rouge
See Vietnam Factor under SOVIET STRATEGY IN SOUTH EAST ASIA
http://www.jstor.org/pss/2644070
The Vietnamese invasion in Kampuchea and the consequent conflict between China and Vietnam has yelid significance strategic gains for Soviet Union. In less than five years it has become a major military power in South East Asia, a near equal to the U.S. Through Vietnam, the Soviet have acquired the use of three military bases and an ally that is powerful military force in its own right, with one of the largest army in the world.
Although the alliance was formed out of mutual need -Vietnam needed the USSR in order to take Indochina and the USSR needed the Vietnamese expansion to extent its influence in South East Asia ....