The Chinese government decried protests in Hong Kong as a “flagrant challenge” to the system under which it allows the territory a degree of autonomy, and it backed a crackdown on the “violent criminals” who rampaged through Hong Kong’s legislature. In another sign that it is increasingly tiring of restraint, Beijing also issued strong warnings to world powers to stay out of its domestic affairs, noting that Western countries have used “extremely strict” measures to quell protests. The warnings underscore a dilemma for Beijing: How long can and should Hong Kong be allowed to remain so defiant before it becomes ungovernable by Beijing’s strict standards?