The corruption probe into former public security tsar Zhou Yongkang will not lead to investigations of other top party leaders, even though it has broken a long-standing agreement protecting the most powerful officials from scrutiny, political analysts said.
The move against Zhou - one of the nine members of the Politburo Standing Committee under former president Hu Jintao - was endorsed after intense discussion during the party's key annual meeting at Beidaihe in Hebei.
The investigation of Zhou, first reported by the South China Morning Post yesterday, would represent the first time a current or former member of the Politburo's supreme Standing Committee has been probed for economic crimes.
"If we apply the same criteria, even more senior officials should be investigated," said Li Xigen, an associate professor at the City University of Hong Kong.
"But I don't believe the authorities are willing or able to launch another investigation of this scale."
Other analysts agreed Zhou's case was a one-off. They said Zhou was being probed because he had become politically vulnerable and the signs of corruption were too strong to ignore.
Zhang Lifan , a historian and political commentator, said: "From a [broader] political perspective, investigating Zhou will bring an end to the tacit agreement not to investigate a Politburo Standing Committee member [for corruption]. "This case will set an important precedent. There won't be any untouchable in the future political struggles."
Some Standing Committee members have been purged and even prosecuted - especially during the Cultural Revolution - but their cases were related to ideology or management failings, not corruption.
Zhang Ming , a professor of political science at Renmin University, said that top party leaders agreed not to initiate criminal investigations against each other after the Cultural Revolution. The move was designed to restore political stability and bring the warring factions back under a single banner.
"This [case], if it is true, would break this tradition," Zhang said. "The future political struggle will become more intense."
The probe of Zhou is bound to raise people's expectations about what could be in store for other top leaders facing questions about the sources of their family's wealth.
The New York Times reported last year that the family of the then premier, Wen Jiabao , had accumulated a vast hidden fortune, a claim the Wen family has denied through lawyers.
Jia Qinglin - who once ranked fourth in the power hierarchy - has been dogged by questions about corruption that happened under his watch as party secretary of Fujian .
President Xi Jinping , who pledged to clean up corruption when he came to power, needs to score a big and early victory to galvanise his campaign.
"Different camps must have their own reasons for bringing down Zhou," said Steve Tsang, head of the China Policy Institute at the University of Nottingham.
"But one common ground shared by everyone is how much Zhou is disliked and how he lost respect among his colleagues - retired or sitting. I can see why Xi [Jinping] finds him an easy target," Tsang said.
Tsang said even former president Jiang Zemin - the political patron of Zhou - wanted to distance himself from the unpopular security chief.
He added: "[Jiang] does not want to be weakened by the Zhou case. He can take the moral high ground and let Zhou go. There is not a single compelling reason for him to defend Zhou."
With another key Zhou ally, disgraced former Politburo member Bo Xilai , being tried for corruption last week, Zhou was left in the no-man's land of Chinese politics. "[By investigating Zhou], Xi will firmly establish himself as a powerful leader, not just a 'first among equals' like Hu Jintao," he said.
A professor in Shanghai, who declined to be named, said: "Investigating Zhou is in line with Xi's character and his upbringing as a princeling" - referring to the president's confidence in his mandate to rule.
Sources and analysts all said a case like this would take months to prepare and probably started well before the trial of Bo.
But they said Beijing would not publicise Zhou's case with Bo's trial only just completed.
"They will have to wait until Bo's case is firmly behind us, otherwise the political impact will be too great," said the professor in Shanghai. Tsang said Beijing needed to carefully evaluate all the possible reactions and would announce it only when it has the full confidence that everything will be under control.
"To bring Zhou down as the biggest tiger, it would have to be a public affair. To maximise the impact, this [announcement] would be timed for a later date, after the public have fully taken on board the effect of Bo's trial," he said.
Regardless of Zhou's fate, the probe will have wider implications. The Shanghai professor said: "It will trigger public anger over the injustice and wrongdoings in China's legal and law enforcement sector [which Zhou controlled for a decade]. It may trigger a bigger [than expected] reaction from the public."