Yao Shuping has understood the perils of one-man rule ever since teenage fanatics came for her mother in the summer of 1966.

It was “Red August”, and as Chairman Mao plunged China into a decade of carnage, Red Guards stormed He Dinghua’s home, ransacking the apartment, shearing off her hair and pummelling her with a nail-studded plank. Finally, they slit the housewife’s throat, condemning her to the mortuary of Beijing’s Number Six People’s Hospital where, days later, her daughter found her corpse as it was carted off for cremation.

“She left this world … her feet bare and blue, her heart filled with terror,” Yao, then 26, recalled in a written account of her mother’s ordeal at the start of Mao’s Cultural Revolution. “It never once occurred to her that she would be sent to her death by the ruthless struggle launched by the great man she worshipped.”

Memories of those murderous years have resurfaced with the shock announcement that China’s current leader, Xi Jinping, is seeking to set himself up as ruler for life by abolishing presidential term limits. These rules were written into China’s constitution in 1982 – six years after Mao’s death – precisely to guard against the kind of personality-led lunacy that destroyed Yao’s family, and so many others.

“To build the fate of a country on the renown of one or two people is very unhealthy and very dangerous,” warned Deng Xiaoping, Mao’s successor and the man behind the political reforms.

“Deng would not tolerate the cult of personality that Mao happily indulged in,” Ezra Vogel wrote in his 2011 biography of the founder of Chinese state capitalism. “Virtually no statues of Deng were placed in public buildings and virtually no pictures of him hung in homes.”

Yao Shuping at her home in Massachusetts. Photograph: Rick Friedman/The Observer

After five years of relentless political purges and arrests, few harbour any illusions about Xi’s authoritarian inclinations. China’s 64-year-old leader has waged war on dissenters, both inside and outside the Communist party, in a drive to establish total control, crushing civil society and jailing rivals to ensure his coronation as China’s most powerful leader since Mao at last year’s party congress.

Even so, for those who witnessed and suffered the excesses of Mao’s megalomania, Xi’s power grab – which paves the way for him to lead China well into the 2030s – has proved a step too far, leaving them fearful their country is slipping back towards its tumultuous past.

In perhaps the boldest public expression of dissent, Li Datong, a former newspaper editor, reminded the Communist party that it introduced term limits “after the immense suffering [wreaked] by the Cultural Revolution” and urged legislators to block the move when they convene in Beijing this week for their annual summit.

Yao Shuping’s mother, He Dinghua, was murdered by Red Guards during the Cultural Revolution. Photograph: Courtesy of Yao Shuping

“This was the highest and most effective legal restriction preventing personal dictatorship and personal domination of the party and the government … It was also one of the most important political legacies of Deng Xiaoping,” Li protested in an open letter.

“China can only move forward on this foundation, and there is emphatically no reason to move in the reverse direction,” he continued. Abolishing term limits would plant “the seed once again of chaos in China, causing untold damage”.

One of the few prominent voices to come out in defence of Xi’s move – the editor of the party-run Global Times newspaper – dismissed Li’s critique.

“I don’t think there will be many people following him,” Hu Xijin tweeted. “Such a move won’t have an impact.” In a video commentary, Hu rejected criticism of Xi’s plan as the work of “sharply voiced” western journalists, whom he labelled “up-to-no-good attackers” set on stifling a rising China. “None of their vicious, ill-fated predictions against China will ever come true,” he vowed.

Beijing has also tried to minimise public anger, particularly among the educated urban elite, claiming there is popular support for the amendment. “I hope everyone can acknowledge the voice of all the Chinese people,” said foreign ministry spokesman Lu Kang.

An editorial in the People’s Daily, the Communist party’s official mouthpiece, claimed the move was aimed at “modernising China’s system and capacity for governance”. Amendments to China’s constitution will ensure the long-term stability of the party and the country, it said.

Li Datong predicted they would have the opposite effect. In an interview with the Observer, the former journalist recalled how his family received relatively “mild” treatment during the Cultural Revolution: he was exiled to Inner Mongolia, while his father had his legs broken and was confined to a “cowshed” prison camp for over a decade.

They stuffed a sock into my father’s mouth and took him away Li Datong

“I can still remember the scene when a group of people came for my father. They stuffed a sock into my father’s mouth and took him away,” Li said. “Many others suffered far more than that. Families were ruined; people died … There is almost no one who was not affected by the Cultural Revolution.”

But Li said Xi’s power grab had left him concerned that China is now on the verge of an “even darker and more terrifying situation” than it faced during that period. Experts estimate that anywhere between 500,000 and two million people were killed in the Mao-era upheaval.

“How can you allow such a dictatorship to recur?” he asked pointing to Mao’s Anti-Rightist Movement and the Great Famine of the 1950s, when tens of millions starved to death in the dictator’s deranged push for breakneck industrialisation. “Limitless power will lead to a situation like that.”

Li insisted he did not fear the consequences of speaking out, although he had heard that the author of a similar petition had been visited by police. “I’m not afraid. If I was afraid, I wouldn’t have spoken out over this,” he said. “My letter didn’t break the law. A citizen expressing his or her opinion is the most natural thing. If anyone regards my letter as illegal, then they should just come straight to me and talk to me.”

But Zhou Fengsuo, a California-based dissident who fled China following the 1989 Tiananmen crackdown, said he admired Li for daring to challenge Xi. “This is definitely a very difficult and challenging time for the freedom fighters and the dissident community. Even within the Communist party I think people are afraid to raise any objections.”

I think of him as the supreme ruler. He’s got at least another 20 years Roderick MacFarquhar

Roderick MacFarquhar, author of the seminal Mao’s Last Revolution, said he and many other foreign China specialists had long suspected that Xi, who took power as party general secretary in 2012, would seek to remain president beyond the originally anticipated decade.

“I think of him as the supreme ruler,” he said. “He’s now 64. So he has got at least 20 years [left in him] … that would take him almost to the centenary of the establishment of the People’s Republic [in 2049].”

But MacFarquhar said Xi’s bid to scrap term limits had given Chinese intellectuals a rude awakening. “They’ve suddenly realised this guy is going on for ever … There must have been a faith in the early 1980s – a hope, I suppose – that a new dawn was dawning and for a time it seemed to be … But they are back to realising that this is, in fact, the same country as Mao ruled and it has now got a Mao-type ruler.”

The Harvard University professor said he believed Xi – with the military’s backing – is so dominant that it is possible to imagine his portrait being hung beside that of Mao in Tiananmen Square in the not-too-distant future.

“I think Xi Jinping at some stage might well say: ‘We have got to hammer home that Chairman Mao was the founder, but I am the continuer … [and] by putting my picture there … people will know we have these two legacies: the Chairman’s, which established the republic, and mine, which rejuvenated the republic.”

Liberals are aghast. “But there is nothing much they can do … As Stalin might have said: ‘How many divisions do they have?’”

Yao may not have divisions but she is certainly determined to keep the memory of the Cultural Revolution alive. She has spent the past three decades fighting to do just that with her written accounts of those chaotic years.

Critics say Xi Jinping could go as far as getting his portrait hung next to Chairman Mao’s in Tiananmen Square. Photograph: Mark Schiefelbein/AP

Yao stressed that she was not predicting an exact repeat of the Cultural Revolution, when Mao unleashed Red Guards on supposed enemies of the people in a cynical attempt to reassert control over the party. “It’s possible it wouldn’t be totally the same ... [but] pretty similar.”

She understands the risks only too well: her family tragedy did not end with her mother’s murder in 1966. Two years later, her brother was accused of being a counter-revolutionary After hearing the news, her inconsolable father, Yao Jianming, decided he could no longer go on.

“That night he hanged himself in his grass hut,” she recalls in her chronicle. “Villagers took his body up into the mountains, where the weeds flourished around it, and he was lost to the living.”

This article was amended on 13 March 2018 to clarify quoted material.