China is intimidated backing out in its ally why?

China has way more money than the US right now and their military expenses are only second to the US! They are afraid of the US but the US is afraid of them too. The US backed off when China took over Tibet. The US backed off when it's known North Korea gets nuclear secrets from China. Now China backs off too! The US knows China will have the largest economy in the world in a few years and knows being friends with China is better than being enemies. The Chinese also think of the US as better allies because most products in the US are Chinese owned and China makes way too much money from American consumers so China does not want to ruin that economic relationship too.