The murmurings of opposition suggest that Mr. Xi and his underlings have not yet fully sold the idea to a broader public — or even done much to explain it.
Far from debating the issue, state media has treated it as a routine matter. So did several delegates when asked about the change.
In the meantime, censors and law enforcement officials have been working overtime to stamp out public criticism, aiming to ensure that nothing clouds the pageantry of the gathering, which continues until March 20, punctuated by an address from Mr. Xi.
According to rights activists, several people who have publicly mocked or criticized Mr. Xi’s plan have been detained or questioned in recent days.
Huang Fangmei, an activist in the central Chinese city of Wuhan, was detained this month and remains in custody, according to friends. She had helped make a video showing a group of people pulling a man in a chair backward as they said, “backing up.” The video was made to suggest that Mr. Xi’s move would set China back in history, Ms. Huang’s friends said.
“Authorities are forced to detain, silence and censor critics of Xi Jinping’s power grab to give it the veneer of public support,” said Frances Eve, a researcher for Chinese Human Rights Defenders , an advocacy group. “With Xi working to cement himself at the core of the Chinese nation, citizens that mock or joke about his rule will likely face further harassment and detentions.”
In Lengshuijiang, a city in Hunan Province, a directive from the regional justice bureau warned lawyers and law firms that they could face disbarment for expressing opposition to the constitutional changes.
The letter, which was circulated widely online and first reported by The Wall Street Journal, requested that “all law firms and every lawyer attach great importance to maintaining consistency with the Party Central Committee,” according to a translation of the message by China Digital Times. The site also reported that university professors had been warned not to debate the issue with students.
Shen Liangqing, a former prosecutor in the eastern province of Anhui, was briefly detained this week for criticizing the decision to end term limits on social media, activists said. Mr. Shen, a frequent critic of the government, wrote on Twitter on Wednesday that he had returned home. “Computer and mobile phone were all confiscated,” he wrote. “Haven’t slept for more than 20 hours.”
The gathering in Beijing is striking for the aura of conformity it seeks to project in what is ostensibly a deliberative body, but where the outcome is rarely in doubt.
“What China is afraid of most is the division of the country,” one delegate, Lu Caixia, said as she entered the congress this week.
She said the constitutional change would be beneficial to the stability of the nation. “The unification of the country and the rule of the party is a Chinese characteristic.”
The orthodoxy of delegates — as well as the polished, regimented displays inside the Great Hall of the People even by the staff marching with fire extinguishers — has exposed the Communist Party to what is often the last resort for dissidents in authoritarian systems: humor.
On the social media and chat app WeChat, someone going by the nickname Xiao Yang posted screenshots of a video of delegates answering a BBC reporter’s dogged questions about the congress and the looming changes with bromides. One delegate told the reporter, Stephen McDonell, that the change “shows Chinese democracy.”
“Damn right,” the author wrote in posts that were swiftly blocked. “This answer reached a new high! All of these are certainly the best explanations of our nation’s democracy! Long live the Socialist Democracy with Chinese characteristics!”
Students at Tsinghua University hung a banner celebrating an unofficial girls day — the day before International Woman’s Day on Thursday — poking fun at the issue of term limits.
“Loving you has no time limits,” one banner said. “If there were, they would be deleted.” The banners were swiftly removed, while the question-and-answer forum where images of the banner first appeared, Zhihu, blocked the post.
A poem by an anonymous author has circulated on social media and among China analysts. It is called “I Object,” and though it was written before the constitutional changes were announced, it clearly tapped into a sentiment shared by some in today’s China. Geremie R. Barmé, the editor of China Heritage, translated and posted it. It ends:
I object to the white noise of the world
I object to the pretense of equanimity
I object to self-justifying truths
I object to blatant ignorance
I object to the tomorrow that’s been promised
I just want you all to join me in shouting:
I OBJECT
