I think is the other way around. Why would the US be scare of China? I don't know where did you get this concept? I say China will be big trouble by not having a trade with US. That is why US goverment wanted to give free trade to LAOS PDR, but not much things to imported from laos. I wish in the future Laos PDR will have a good trade with US and many of Laos Americans are looking into that.
American GDP 19 trillion a year for 310 milions people. Japan GDP 12 trillion a year for 128 milions people. China GDP 6 trillion dollars a year for 1300 milion people.