Funny you mention the Tang dynasty. The downfall of Tang start from An Shi Rebellion, a Turkic ancestry general lead a 150,000 strong force made largely from non-Han Chinese try to take over the empire, which is the bloodiest war in human histroy until WWII.
All future ruller of China, Han or non-Han, take leason from this event, and doing what they can to ensure the purity of the ruling class. Han use Imperial examination to block minority out of ruling institution. Mongols not allow Chinese (Han or non-Han) to take important position in goverment. Manchus use literary inquisition and dual appointments to ensure Manchu rule and Han loyalty. Japanese stop teach Chinese and Korean in school and puting spies in the puppet government and amount public.
Obama dont mean anything to minority in China. He is an English speaking, Amercian educated Christian, who belive in the idea of American as a super power.
If a minority in China is a Chinese speaking, Chinese educated CCP member, the chance for him/her to get in to poltiburo or other central government body is also very good.
Ordie, the Tang period may be considered by many in the West to be China's golden era, but scratch the surface a little deeper, and you will find Tang to be a pretender to the throne.
Read up on Sui Dynasty, a very short lived dynasty before Tang, and you find that all the hard work has already been done and that the Tang literally just took over and claimed the credit for the hard work. A bit like Qin/Han...
The AnLuShan rebellion happened in the reign of only the 3rd Tang emperor, and pretty much it was down hill from there. Then there was the Zhou dynasty interruptus before things continue downward.
So no I dont see the irony.
As for my pick, its Ming and Qing.
Ming is the pinnacle of "Sinica", and its influences (cultural, economic, political, and social) continued even onto the next dynasty and beyond, not to mention its influences around the region. Economically they accounted for 1/3 of the world. Ming also has a distinction of not marrying off their royals in order to maintain peace with tributary states - its either peace on our terms or war (althought they had some embarrassing defeats). They symbolically moved the capital from Nanjing to Beijing, where it remains.
The irony with the Ming were their rulers tend to be nutters more often the case than not, and the country was mainly run by the public servants and the eunuchs. The period was characterized by effective government rather than good rulers.
Qing is the pinnacle of "China" (as a geopolitical entity), its borders reached the fullest extent, where the writ of the state was firmly established into previously contested ground (Xinjiang, Tibet, Taiwan...cough, cough). The current PRC border owes much to the legacy of the Qing. Militarily and economically they were at one stage (I have to say around the early 1700s to mid 1700s) the pre-eminent power in Asia, if not the world.
The irony here is of course the Qing dynasty were a bunch of "minority", whom become more Sinicized than even the ethnic Hans themselves. Plus they have the infamy of being the last ruling dynasty that presided over a 200yr decline culminating in the weakest period of Chinese history. In a sense, China already had its experiment with minority rule. Ironic isnt it.
So yes China, its history and its people is full of ironies, but sometimes not the ones you think.
So much so that a Ming General was bribed by the Manchus to open the gates at the Great Wall and led to the establishment of the Qing Dynasty.
In all, what saved Chinese Civilization was the "Mandate of Heaven" concept and its strong bureaucracy. But over time, China became so inward looking that it could not recover by the time of the First Opium War.