My guess as to who (or what) will restrain their behavior: demographics. China is a dynamic country with a powerful economy, but they also have a enormous demog

My guess as to who (or what) will restrain their behavior: demographics. China is a dynamic country with a powerful economy, but they also have a enormous demographic time bomb ticking (an aging population and a low birth rate - one that isn't responding that well to relaxing population control laws). Also, as for violently annexing territory, they are mild-mannered compared to pretty much every other 'young superpower'. It's worth putting this in perspective with the historical behavior of European superpowers as well as the USA and USSR.