The violence in Hong Kong
The protesters aren't asking for much. Their chief demand now seems to be the resignation of Hong Kong's chief executive, CY Leung. It's not like they're asking for the kind of freedom that Americans, Europeans, or Japanese take for granted every day.
It's even remotely conceivable that the Beijing regime might decide to meet this demand, sacrificing one interchangeable apparatchik for some peace and quiet. But I think it's unlikely. The regime learned an important lesson from perestroika in the USSR -- start making any concessions to the masses at all, and the whole system could start to unravel and eventually collapse. So their preferred response is a crackdown, no more brutal than necessary to crush dissent, but no less either.
Don't be surprised if the final act in Hong Kong is every bit as bad as in Tienanmen Square.
The Beijing regime is a brutal fascist oligarchy of murderous thugs who are willing to kill however many of their own subjects they need to in order to stay in power. It's not any more complicated than that. Westerners like to try to delude themselves otherwise (and there's already signs of the predictable drip-drip of vomitous editorials and blog posts striving to "understand" and legitimize the regime's position), and the psychological reasons for this are straightforward enough. But what Westerners convince themselves of inside their own heads does not change the reality on the ground in China.