BEIJING — Even in a moment of triumph, China’s president, Xi Jinping, exudes anxiety.

Since the Communist Party gave Mr. Xi the exalted title of “core leader” last week, it has built a fervent campaign to rally the country around him. The symbolic boost has underscored Mr. Xi’s dominance of the party elite, raising the chances that he will get his way in a reshuffle of its top ranks next year.

But this victory at the top for Mr. Xi has been laced with warnings in official documents and speeches about risks facing China and the party: a slowing economy distorted by excessive debt and unneeded industrial output, worries that corruption could rebound, bureaucratic inertia frustrating central policies, and international tensions.

Mr. Xi appears politically indomitable, but officials suggest he and other leaders are alarmed by broader, long-term dangers and by the party’s ability to weather them. Both considerations underpinned the leadership’s decision to go along with raising his status.

“Maintaining a sense of peril is a part of the traditions of the Communist Party,” said Wang Wen, a professor at Renmin University in Beijing who has met Mr. Xi. “But his sense of peril goes deeper than recent leaders’.”