In truth, China is more vulnerable that the US is. Yves has some good stuff on this today. Here's more from the FT's Abrose Evans Pritchard:
It is fashionable to talk of America as the supplicant. That misreads the strategic balance. Washington can bring China to its knees at any time by shutting markets. There is no symmetry here. Any move by Beijing to liquidate its holdings of US Treasuries could be neutralized – in extremis – by capital controls. Well-armed sovereign states can do whatever they want. If provoked, the US has the economic depth to retreat into near autarky (with NAFTA) and retool its industries behind tariff walls – as Britain did in the 1930s under Imperial Preference. In such circumstances, China would collapse. Mao statues would be toppled by street riots.