Ok you are wrong on both counts. China is still a third world country although it is developing at a phenomenal rate. 90% of the Chinese population are rural farmers who make barely anything. The U.S. economy is also much larger than China's and more stable for that matter. Although the Chinese government has bought a lot of U.S. debt, they depend on us just as much as we depend on them. If China tried to call in all our debt the value of the dollar would plummet and the billions of dollars in U.S. treasury bonds that China has would be worthless. Sure, they could mess up our economy but they would just be destroying themselves.