According to the theory of clash of civilization, the main threats for western civilization is Muslim civilization and sino(Chinese) civilization, though westerners recently were defeated in Afghanistan after twenty years of fighting, Muslim civilization is not at a stage to challenge westerners as they are still far back in terms of technological advantages of modern warfare. so right now their main challenge comes from china. China is advancing swiftly if it advances at that pace and can use the benefits of the huge young population right now and few more decades, they can challenge the west. furthermore china got some friends like Russia and Iran and North Korea.it is important here to know that the US and allies spent billions of dollars in Afghanistan in the last twenty years because Afghanistan has borders with China and Iran and it is very near to Russia. so if it was under their control, it was very easy to threaten those countries. also westerners were interested t...