Mr. Xi has not publicly addressed the political tumult in Hong Kong. Nor have officials disclosed any options they might be considering. But there is little doubt about Mr. Xi’s convictions, which are shaped by history and a deeply felt sense of the perils of popular uprisings.

“I have heard him talk at length, and passionately, about the challenges of governing China, and the need to maintain order in order to keep the country together,” said Ryan L. Hass, a fellow at the Brookings Institution who served as the director for China at the National Security Council during the Obama administration.

He noted that the mass protests that toppled authoritarian governments in North Africa and the Middle East in 2011 coincided with Mr. Xi’s ascent to the presidency and were “seared into his brain.”

Mr. Xi’s stance is not without risks, but he has governed with a millenarian sense of destiny, regularly exhorting the Communist Party to return to its original mission to transform a once-humiliated nation into the global power it is meant to be.

While the events in Hong Kong have generated considerable sympathy for the protesters, forcing the city’s leader to back down and suspend a deeply unpopular bill that would allow extradition to China, Mr. Xi still has most of the advantages of power on his side.

Those include time and influence. The central government can still mobilize a vast network of supporters in Hong Kong, including civil servants and business people beholden to the central government, economically or politically.

In a last resort, there is also the Chinese military. Few analysts expect that Mr. Xi intends to use force, but few doubt that he would if security significantly deteriorated in the city.