At the 20th National Congress of the Chinese Communist Party, starting on Sunday , Xi Jinping will almost certainly be confirmed for a third term ^[1] as the party’s general secretary and China’s president. With that, he will become China’s longest-serving ^[2] paramount leader since Mao Zedong, and the rules and norms that are supposed to govern the CCP regime will be shattered.

Those rules and norms were put in place largely by Mao’s successor, Deng Xiaoping, who took power in 1978. Deng knew firsthand the damage the party’s ideological fanaticism could do. During the Cultural Revolution, one of his sons was paralysed ^[3] by rampaging Red Guards. Deng himself was stripped of his official positions and sent to work at a factory ^[4] in a remote province for four years—one of three times ^[5] he was purged from government during his long revolutionary career.

To ensure that China would never again be gripped by such terror, Deng—with the support of other veteran revolutionaries who had survived the Cultural Revolution—restored collective leadership and imposed age and term limits ^[6] for most senior CCP positions. In the decades that followed, China’s top leaders served no more than two terms, and Politburo members respected an implicit age limit of 68 ^[7].

But Xi has exposed just how fragile Deng’s ‘rules-based system’ really was. In fact, for all the hoopla about Deng’s accomplishments, his record on reining in the CCP regime is mixed, at best, not least because his own commitment to the rules was not nearly as robust as one might expect.

In practice, Deng disdained collective leadership and formal procedures. He seldom held Politburo Standing Committee meetings ^[8], because he wanted to deny his main rival, a staunch conservative opposed to economic reform, a platform to challenge his policy. Instead, he exercised leadership through private meetings with supporters.

In dealing with leaders sympathetic to pro-democracy forces, Deng frequently violated the procedures and norms he had established. His dismissal of two liberal CCP chiefs ^[9]—Hu Yaobang in 1986 and Zhao Ziyang (who refused ^[10] Deng’s order to implement martial law during the Tiananmen crisis) in 1989—defied the party’s bylaws ^[11].

At the same time, Deng sometimes avoided introducing a rule at all, if doing so could undermine his political interests. Most notably, he—together with other ageing CCP leaders—did not impose age or term limits on Politburo members ^[12]. Even if they could not hold formal government posts indefinitely, they would never lose their decision-making authority.

Likewise, Deng enacted no formal rules governing who could chair ^[13] the Central Military Commission. This enabled him to continue to do so ^[14] after he had resigned from his other posts. Following that precedent, Jiang Zemin did the same in 2002. As for Xi, while he had to go through the motions of getting the presidential term limit removed from the constitution ^[15] in 2018, he benefited from the fact that the CCP has not imposed an official term limit ^[16] on its general secretary.

There is nothing shocking about China’s struggles to uphold rules and norms. Even mature democracies like the United States face such challenges, as Donald Trump’s presidency clearly showed. But should formal constitutional checks and balances fail, democracies can at least count on a free press, civil society and opposition parties to push back, as they did against Trump.

In dictatorships, rules and norms are far more fragile, as there are no credible constitutional or political enforcement mechanisms, and autocrats can easily politicise institutions, such as constitutional courts, turning such bodies into rubber stamps. And there are no secondary enforcement mechanisms. China has no free press or organised opposition ^[17]. If a rule becomes inconvenient—as the constitutional limit on presidential terms did for Xi—it can easily be changed.

While trampling institutional rules and norms may benefit autocratic rulers, it is not necessarily good for their regimes. The CCP’s experience under Mao is a case in point. Unencumbered by any institutional constraints, Mao engaged in ceaseless purges and led the party from one disaster to another, leaving behind a regime that was ideologically exhausted and economically bankrupt.

Deng understood that a rules-based system was essential to avoid repeating that disastrous experience. But his conviction could not overcome his self-interest, and the institutional edifice he built in the 1980s turned out to be little more than a house of cards. Xi’s confirmation this month is merely the breeze triggering its inevitable collapse.