One hundred years after thousands of Chinese students marched on Tiananmen Square in a watershed revolt, President Xi Jinping seized on the event Tuesday to burnish his brand of authoritarian nationalism. Mr. Xi gave a stark display of the Communist Party’s determination to control the legacy of the movement that has inspired both friends and foes of party rule.

The May 4, 1919, protest against Western colonialism had inflamed Chinese nationalism and helped spread a wave of ideas rejecting Chinese tradition and hierarchy. In a speech marking the centenary of the event, Mr. Xi extolled the patriotic image of May 4 while ignoring its anti-authority themes.

“History profoundly reveals that patriotism has flowed in the blood of the Chinese nation since ancient times,” Mr. Xi said in the Great Hall of the People, next to Tiananmen Square. “Those who are unpatriotic, who would even go so far as to cheat and betray the motherland, are a disgrace in the eyes of their own country and the whole world.”

“Chinese youth in the new era must obey the party and follow the party,” Mr. Xi said.

May 4 is one of several politically charged anniversaries that the Communist Party must carefully manage — or muffle — this year. The party has reason to be on guard: The anniversary of May 4 has prompted protests in the past, including pro-democracy demonstrations at Tiananmen Square in 1989 that soldiers extinguished in a night of carnage on June 3-4 that year.