As a joke circulating among Beijing's elite suggests, Vice-President Xi Jinping, who is slated to take over power in November, owes much thanks to a now-infamous face slap early this year that changed history.
In January, Bo Xilai , the now-disgraced former party secretary of Chongqing, raised his hand to then aide and municipal police chief Wang Lijun after the latter confronted Bo with allegations that his wife was involved in the killing of British businessman Neil Heywood.
The subsequent developments saw Wang flee to the US consulate in Chengdu with incriminating evidence against Bo and his wife, leading to the biggest political crisis the Communist Party has faced in recent decades, which culminated in Friday's announcement that Bo had been expelled from the party and would face criminal prosecution.
Before the January confrontation, Bo, the flag bearer of the mainland's leftist movement, was an odds-on favourite to join the Politburo Standing Committee - the mainland's highest governing body - in the once-in-a-decade leadership transition to be approved at the 18th party congress, now scheduled to begin on November 8.
Just imagine if Bo had reacted differently to Wang, and if the murder scandal involving his wife didn't come to light until after the congress. Bo would most likely have been in power as a Politburo Standing Committee member. Never has a member of the committee been sacked or arrested for a non-political reason.
Many mainlanders, including law students, have also subscribed to the conventional belief that those political elite are above the law. And given Bo's ambitious and ruthless nature, he would have surely been a wolf among sheep on the committee, meaning that history would likely be on a much different course.
That would have been a scary thought for Xi and the other incoming leaders. So it is no wonder that, according to a report by the quasi-official mainland news agency based in Hong Kong, President Hu Jintao and Xi joined hands in calling for Bo to be punished harshly.
An even scarier thought is that mainland leaders were reportedly divided on how to deal with Bo after the scandals broke. This led to months of political uncertainty about the party's plan to install a new generation of leaders, including Xi, who will take over as president, and current Vice-Premier Li Keqiang , who will be named premier.
Some within the party reportedly sought leniency for Bo, suggesting he be disciplined internally rather than face criminal charges.
But now Bo is out of the game, and the leadership has trumpeted his expulsion and the prospect that he will face criminal charges, calling the moves unmistakable signs of the fight against corruption and vowing "no mercy for corrupt officials, no matter who is involved or how great his or her power is".
In fact, there are deeper reasons for Bo's harsh punishment. As a charismatic leader, Bo's populist policies and open embrace of Mao Zedong's egalitarian era had won him strong support among the country's leftists, who have been unhappy about official corruption and the nation's rising income gap between the rich and the poor.
Harsh punishment of Bo serves also to help curb his support group, particularly after recent waves of anti-Japan demonstrations saw some protesters holding up pictures of Mao - an action seen by many as a show of support for Bo.
Thus came Friday's official announcement of serious allegations against Bo, including that he took bribes worth huge amounts of money, abused his power in the investigation into his wife's involvement in Heywood's murder and maintained improper sexual relationships with several women.
Bo's wrongdoings are said to have spanned nearly 20 years, starting from his early days as the mayor of Dalian in Liaoning , then as the province's governor, as the minister of commerce and finally as Chongqing's party secretary while serving as a Politburo member.
The mainland's top leaders may think they have gone for the jugular, but this could backfire, as it is likely to enrage the public and embolden people to raise questions about the party's anti-corruption efforts and the extent of corruption within it. More importantly, it will lead to questions over one-party rule and result in more calls for political reform.
Indeed, if Bo was corrupt 20 years ago and committed wrongdoings ever since, why was he not stopped earlier?
The detailed allegations involving Bo, his wife and his police chief have shown that they held little regard for the law.
If Bo, as the party secretary of Chongqing, lived above the law, what about the party chiefs of other provinces and municipalities, and those leaders in the central government?
The more that mainlanders demand answers to those questions, the more scared Chinese leaders should feel.