On Sunday, hundreds of thousands of people marched again in Hong Kong despite the government’s concession a day before, insisting that the legislation be withdrawn while making new demands, including for an investigation into the use of excessive force by the police in clashes with protesters. The large turnout was a surprise, and it means the crisis is not over for Mr. Xi. Given how he has consolidated power in China, he may find it increasingly difficult to avoid blame.

The risk for Mr. Xi is not limited to Hong Kong. Though he has no visible rivals, he may face criticism in the leadership. And the mainland government’s censors, at least, are clearly concerned that the extraordinary events might inspire Mr. Xi’s beleaguered critics in mainland China, and they have been working vigorously to block the news from spreading.

[Protesters in Hong Kong once again took to the streets on Sunday.]

“This further chips away at the image of Xi as an all-powerful, omnicompetent and visionary leader,” Mr. Blanchette added.

The demonstrations also made clear that after 22 years, Beijing has had minimal success in weaving Hong Kong into the country’s central political, economic and security systems, all dominated by the Communist Party. But if Mr. Xi and his cadres want to proceed more forcefully to bind Hong Kong to the mainland, they must also see how that could invite new waves of protest.