Discussions on the rule of law are set to dominate a top leadership meeting later this year as Beijing tries to build consensus for an announcement on the graft investigation into former security chief Zhou Yongkang. The date of this year's Communist Party Central Committee plenum is also likely to be brought forward as pressure grows for the leadership to make a final decision on Zhou. The plenary session traditionally takes place in September. But several sources told the South China Morning Post that party leaders were considering bringing it forward, although the exact date had yet to be decided. The leadership meeting usually maps out the party's administrative and ideological development. Senior appointments are often announced, paving the way for more government reshuffles. It is understood that President Xi Jinping may use the meeting to pledge to safeguard the constitution and fight graft, even at the top of government. This will help to rally the party elite and convince them the investigation into Zhou was part of the campaign to bolster the rule of law, not a political power struggle as some have suggested, several sources with knowledge of the matter said. Zhou, once a member of a nine-man Politburo Standing Committee of top leaders, has been in detention since December for alleged corruption. The investigation into Zhou may be announced around the time of the annual meeting, two sources said, adding that it remained unclear if the authorities would hand the case over to prosecutors to press formal charges. An earlier briefing for senior officials was told the investigation into Zhou would deal only with alleged financial wrongdoing and corruption and that the sums of money involved would be far less than reports have suggested, a person familiar with the meeting previously said. Zhou was head of the Central Politics and Law Commission - which oversees the courts, prosecutors and police - before he retired in November 2012. The government spent more money on domestic security than defence under Zhou to maintain social stability, with activists arguing it gave police too much power and harmed civil liberties. "To promote the rule of law at this stage means a negation of the legal system over the past years, which was under the control of Zhou," said one of the sources. Wang Guixiu, a retired Central Party School researcher, said officials and the public had different perceptions of the rule of law. "The public say it is about putting officials in check, while officials say it is about how to govern the public." The party issued two documents in May last year to set out the internal rules for its 80 million members, which experts said was an attempt by Xi to exercise stricter controls over cadres' conduct. Xi has promised to uphold the rule of law and tackle abuse of police powers, but the public has questioned his sincerity after several cases of rights activists being jailed or detained since his administration took power in 2012.