"More than Iraq, Iran, Syria and North Korea (alone), biggest pontential threats to US are China and Russia. And this the sole reason why US is in Middle East. My point is US need playgroud (Afganisthan and Iraq) to tackle with these threats not just militarily but economically as well. Control over Aghanisthan and Iraq is merely for logistic purpose, if US happen to attack on Iran. " Bingo! now analyze your own paragraph. Russia and China are potential threats to the US. This means, the US has to side with one to deter the other. This means, either US-Russia alliance against China, or China-US alliance to keep Russians in check. I think the US will go with the US-China alliance because it's more sensible. By joining hands with the Chinese, the US will make Russia spend more on its defense because an US-China alliance means Russia spending a lot of $$ on deploying troops in Siberia. From the US perspective it's presence in the Middle East and Central Asia is to keep both China and Russia in check. The Russians don't like the US presence in Central Asia, the Chinese don't like it either but the Chinese would not like to see a heavy Russian presence in Central Asia either. So the US is now equalizing the BOP in that region. In Chinese perspective, the US is encircling China, in the Russian perspective, the US is not being respectful to Russia's position.. its an interesting triangle. But what will happen if and when the US leaves the region? The Russians will immediately take over, which will pose a security threat to China. So its in the best Chinese interests to side with the US and vice-versa because they both have less and less reasons to go against war with each other. I agree with you. The US is trying to control China's energy supply. The US wants to use the energy sources as its trump card in its dealings with China. China has started to look for the energy sources in Latin America and Africa, but as I wrote earlier, given the history of instability in those regions, China cannot be 100% certain regarding uninterrupted energy supplies from those regions. So a common Russian threat will again be a reason to forge a strategic partnership between China and the US. The US knows it cannot stop Russia so it won't make much noise when Japan pumps money to Russia. The US will actually support that because it will let it (US) side with China, and China will have less reasons to complain about growing US presence in the region(s). My views.