China views the fate of Hong Kong as a purely internal affair. But how its leaders resolve the ongoing confrontation on the streets of the former British colony will determine China's external reputation for years to come.

The world sees two Chinas. One represents all that is hopeful and ambitious about Asia: boundless economic growth, 1.3 billion consumers of tomorrow and Alibabas as far as the eye can see. The other reflects a repressive regime that is more bully than global stakeholder. For a week now, as the shadow of Tiananmen has hung over Hong Kong's protests, that second China has once again dominated the headlines.

Chinese President Xi Jinping may think this doesn't matter. For the past quarter of a century, the Chinese Communist Party has believed it got away with its violent crackdown in 1989, when tanks rolled through Beijing. The world's horror and condemnation quickly faded, replaced by an eagerness to benefit from the mainland's 7 percent-plus growth and emerging middle class.