4salt,

You cannot be that dense. Well maybe you are just doing google searches and do not have a working knowledge of the region at that time. The Khmer growing in power under Soviet and Chinese influance allowed them to take over the comunist/socialst effort on the remainder of the Peninsula. Freeing up the NVA which formerly had been operating under Soviet direct in Cambodia, Laos and Thailand in those areas. This allowed the NVA to push the lines and ultimately retake the South with our pull out. Giving the Soviets or the Chinese the option on the entire Peninsula. Had they had the economies to do anything with them which they did not.
You might try a few Google searches about our unoffical operations in Cambodia and Laos in order to understand the role the Khmer played.