Chinese workers save a lot, maybe forty to fifty percent of their incomes. There are some demographic reasons for that but it also suggests fear and foreboding. They wonder if the Chinese economic miracle can continue. There aren't full contingent claims markets in China but this quantity (of savings) is reflecting an implicit price for transferring wealth into possible bad world-states. That implicit price suggests a fair amount of worry.
In the U.S. T-Bill market, in contrast, there is relative optimism and froth. Lots of securities can be sold at rates close to zero. That explicit price suggests not so much worry about the creditworthiness of the U.S. government and not so much worry about China.
The two prices contradict each other and they continue to do so because explicit arbitrage is not possible. (Ideally, at least in neoclassical fantasy land, the U.S. government should be borrowing money from the Chinese and selling them back insurance at a higher price.)
From this portrait you can see why it is so hard to unwind the imbalances. (Many expositions of imbalances focus on quantities and thus may obscure this point somewhat.) If the Chinese workers are dealing with the correct price (implicit price), that means the worries are real and rates in the T-Bill market have to spike. Ouch. If the auction market for T-Bills is showing the correct price, that means the worries are false and at some point Chinese workers won't save nearly so much. Again, rates in the T-Bill market have to spike. Ouch.
Either way it ends in ouch. There's a reason why, rhetoric aside, no one wants to end these imbalances.
So who has the right price? The Chinese workers or the T-Bill bidders? As usual, the truth probably lies somewhere in between.