Misinformation du jour me thinks.
If I had a dollar for every reason the US was on the ropes, I'd be a millionaire several times over.
Price of oil increasing
Wars
Housing prices
Terrorism
Stock market scandals
Debt
Blah blah blah
The US economy is an 800 pound gorilla and the rest of the worlds economies are spider monkeys in comparison.
I'm not saying that the US economy will be number one forever, but they will likely remain number one for at least 30 years. That how long it will take China to surpass them. If they can maintain this type of hyper growth for that long.
The recent stock market crash in China was rumoured to be self inflicted as Chinas government is worried that China's economy is growing too fast to be sustainable.