China, due to demographic issues caused by the one-child policy, and the consequences of its authoritative experience, will not be a sustainable power on the international stage. It is more likely to be too old demographically before it is truly rich enough to develop into a meaningful power and it is likely to implode due to internal political conflicts (city versus rural, Han vs. Uighur and so forth).
This actually makes China more dangerous, not less. It will be a hugely destabilizing force in the international system.
So it appears we are living the famous Chinese curse and living in interesting times.