BEIJING (NYTIMES) - China's top leader, President Xi Jinping, seemed indomitable when lawmakers abolished a term limit on his power early this year.
But months later, China has been struck by economic headwinds, a vaccine scandal and trade battles with Washington, emboldening critics in Beijing who are questioning Mr Xi's sweeping control.
Censorship and punishment have muted dissent in China since Mr Xi came to power. So law professor Xu Zhangrun of Tsinghua University in Beijing took a big risk last week when he delivered the fiercest denunciation yet from a Chinese academic of Mr Xi's hardline policies, revival of communist orthodoxies and adulatory propaganda image.
"People nationwide, including the entire bureaucratic elite, feel once more lost in uncertainty about the direction of the country and about their own personal security, and the rising anxiety has spread into a degree of panic throughout society," Prof Xu wrote in an essay that appeared on the website of Unirule Institute of Economics, an independent think tank in Beijing that was recently forced out of its office.
"It's very bold," Mr Jiang Hao, a researcher at the institute, said in an interview. "Many intellectuals might be thinking the same, but they don't dare speak out."
Mr Xu urged Chinese lawmakers to reverse the vote in March that abolished a two-term limit on Mr Xi's tenure as president.
That near-unanimous vote of the party-dominated legislature opened the way for him to retain power for another decade or longer as president, Communist Party leader and chairman of the military.
The essay appeared as a burst of troubles has given a focus for criticisms of Mr Xi's strongman ways, and it has spread through Chinese social media, despite censors.
Other less damning criticisms, petitions and jibes about Mr Xi's policies have also spread, often shared through WeChat, a popular social media service. But this long, erudite jeremiad from a prestigious professor has carried more weight.
"Xu has written a challenge from the cultural heart of China to the political heart of the Communist Party," said Professor Geremie R. Barmé, an Australian scholar of China who is translating Mr Xu's essay.
"Its content and culturally powerful style will resonate deeply throughout the Chinese party-state system, as well as in the society more broadly."
" Over recent months, China has been grappling with a growing trade dispute with the United States. Some Chinese foreign policy experts have suggested that the trade fights with the Trump administration could have been contained if Beijing had been more flexible and moved faster to douse triumphalist statements about its goals.
"China should adopt a lower profile in dealing with international issues," Professor Jia Qingguo, who teaches international relations at Peking University, said at a recent forum in Beijing. "Don't create this atmosphere that we're about to supplant the American model."
Revelations about faulty vaccines given to hundreds of thousands of children have ignited public anger and protests, especially because the government promised to clean up after similar previous scandals.
On Tuesday, Mr Xi convened a meeting of the Politburo - a 25-member party leadership council - that warned of economic tests while promising to keep growth steady.
The economy was sound but "faces some new issues and challenges, and the external environment has undergone clear changes", the meeting concluded, according to an official summary from Xinhua, the state-run news agency.
The undercurrent of discontent does not pose any immediate threat to Mr Xi's hold on power. He and the Communist Party remain firmly in control. And many Chinese people endorse his tough campaign against corruption and his vows to build China into a great power that will not compromise over territorial disputes.
But party insiders and foreign experts said misgivings about Mr Xi's hardline policies appeared to be building among intellectuals, liberal-minded former officials and middle-class people after the recent misfires.
A former official who spoke on condition of anonymity said that many former colleagues had shared Prof Xu's essay.
Over time, he and others said, such criticism could coalesce into deeper disaffection that erodes Mr Xi's authority and gives other senior officials more courage to question his decisions.
"In recent weeks, the signs of a nascent pushback against Xi's absolute power have started to emerge," Mr Richard McGregor, a former journalist in China who is now a senior fellow at the Lowy Institute in Sydney, Australia, wrote recently.
"The harder question then becomes what that actually means in practice," Mr McGregor said in e-mailed answers to questions.
"If it means heightened infighting in elite politics, it might result in policy paralysis and instability, rather than just a freer and more open debate."
In his essay, Mr Xu challenged another political taboo, urging the government to overturn its condemnation of the pro-democracy, anti-corruption protests that erupted in Chinese cities in 1989 and ended after the Tiananmen Square crackdown. Next year is the 30th anniversary of that bloody upheaval and promises to be a tense time for the government.
"As things continue in this direction, the question arises whether reform and opening up will come to a halt and totalitarian rule will return," Prof Xu said in the essay, written in a densely classical style speckled with recondite phrases and historical allusions.
"At this time, no other anxiety weighs most heavily on most people."
Prof Xu did not answer messages and phone calls, and he is listed as being a visiting scholar in Japan. He may face censure back in Beijing. Some opponents of Mr Xi have been detained and imprisoned for online protests, but the authorities may act more cautiously against an academic from a major university.
Intellectuals and ex-officials sceptical of Mr Xi's agenda are also likely to seize on the 40th anniversary of a party meeting in 1978 that is now seen as inaugurating Deng Xiaoping's era of "reform and opening up".
Party leaders still revere Deng, even though Mr Xi has jettisoned some of his pragmatic policies. But more liberal-minded former officials have also embraced Deng as an icon, casting him as a more moderate leader to highlight the swaggering overreach they say Mr Xi has brought.
"Even though the reality is much more complex, Deng's popular image often boils down to one word: reform," said Mr Julian Gewirtz, a scholar at the Weatherhead Centre for International Affairs at Harvard University who is studying China's changes in the 1980s.
"Today Xi is clearly parting ways with elements of what Deng supported, such as more open intellectual debate, greater separation of party and state, and 'biding time' in international relations," he said. "And for critics of Xi, Deng may be a useful symbolic weapon because of his stature as a particular type of reformer."
Some signs suggest that the trade tensions and domestic criticisms may have already prompted Mr Xi's government to cool the public tone.
A series of articles in The People's Daily scornfully mocked Chinese scholars and pundits who have claimed that China has surpassed the United States as a technological power and warned the news media to curb cocky boasting.
"It's too soon to see if this type of criticism could constrain the leadership, but it is interesting that there has been some recalibration of the foreign policy rhetoric," said Dr Susan Shirk, the chairwoman of the 21st Century China Centre at the University of California, San Diego, and a former deputy assistant secretary of state.
That, she said, "suggests that there is some ability to self-correct, at least on the rhetorical level."
Others see signs that the Communist Party has been cooling its glorification of Mr Xi.
In his essay, Prof Xu said that the propaganda echoed the cult of personality that surrounded Mao Zedong, and he called for "slamming on the brakes".
"The propaganda system has been put on the defensive for contributing to the cult and also messing up the messaging concerning the US-China trade conflict," said Dr Dali Yang, a political scientist at the University of Chicago who studies Chinese politics.
But speculation shared among some of Mr Xi's critics in Beijing and on the Internet that unhappy party officials and elders had forced a full-scale retreat from the adulation appears to be unfounded.
Mr Xi's name has appeared on the front page of the People's Daily as often as ever; the frequency of appearances in July was not markedly down, according to counts made by Mr Qian Gang, a media expert at the University of Hong Kong.
As well, a party campaign to study Mr Xi's years as a youth in Liangjiahe Village in northwest China has continued to inspire rhapsodic reports.
Prof Xu's future may now become a test of whether Mr Xi will display greater tolerance of criticism.
"I have said what I must and am in the hands of fate," he wrote at the end of his essay. "Heaven will decide whether we rise or fall."