Allowing Chinese President Xi Jinping to rule indefinitely will be seen by historians as a farce, a government critic has told the BBC.
In a rare show of public dissent, ex-state newspaper editor Li Datong sent an open letter opposing the proposal.
He says in the letter that scrapping term limits for the president and vice-president would sow the seeds of chaos.
China’s internet censors have been deleting critical comments across Chinese social media platforms.
There had been widespread speculation that Mr Xi would seek to extend his presidency beyond 2023. The party congress last year saw him cement his status as the most powerful leader since the late Mao Zedong.
Why is there opposition?
On Sunday, China’s governing Communist Party proposed removing a clause in the constitution which limits presidencies to two five-year terms.
A day later, Mr Li, the former China Youth Daily editor, sent a statement on the messaging app WeChat to Beijing’s members of the National People’s Congress, China’s rubber-stamp parliament.
Speaking by phone from his home in Beijing, Mr Li told BBC Chinese he was too old to be afraid of the authorities.
“As a Chinese citizen, I have to fulfil my responsibility and tell the delegates my opinion. I don’t care what these delegates will do. It’s not like the whole country agrees with the amendment, but everyone has been silenced.
“I couldn’t bear it any more. I was discussing with my friends and we were enraged. We have to voice our opposition.
“Even if the amendment is passed, it doesn’t matter. History is often like this – we make two steps forward and one step back.
“But this is against the tide of civilisation and won’t stand the test of time. It will be considered a farce in Chinese history in the future.”
Mr Li is not the only critic openly attacking the proposal. A prominent businesswoman Wang Ying wrote on WeChat that it was “an outright betrayal”.
Who is Li Datong?
Li Datong is a veteran journalist who is widely respected. At the time of the interview he said he was free but added that his mobile phone had been under surveillance for years.
Many intellectuals and lawyers have been warned by the authorities not to talk to foreign media or make any comment on social media. Amid this kind of atmosphere, Mr Li’s letter is a bold move.
His letter was soon censored but social media users have find other ways to share it. For example, they took a screenshot of the photo and posted it upside down.
The proposal to remove the presidency’s two-term limit has to be passed by delegates of the NPC in early March. However, the delegates are not directly selected by the public and the NPC is often considered a rubber stamp which passes motions according to the wishes of China’s top leaders.