Party rethinks twin-role postings
The unfolding scandal surrounding Bo Xilai - one of the few Politburo members also tasked with overseeing a municipality - has raised questions within the Communist Party about whether it should continue to appoint top brass as municipal or provincial leaders.
Bo's downfall is officially said to be linked to corruption and the murder case of a British businessman.
Bo is the third top regional party chief to be ousted for corruption or other wrongdoing, after former Beijing party secretary Chen Xitong and former Shanghai party boss Chen Liangyu were sanctioned - prompting growing calls to stop the practice of appointing Politburo members to local posts.
The mainland's four most economically and politically significant mega-cities - Beijing, Shanghai, Tianjin and Chongqing - along with Guangdong, its richest province, are currently headed by Politburo members. Their appointments serve to highlight the importance of these regions and ensure the central government's grip on them.
There are, in theory, five parallel governing institutions - the Communist Party, government, army, people's congresses and political consultative conferences - but the party is dominant. And there are five tiers of government - the central leadership, provinces and ministries, prefectures and departments, and county-level and town-level administrations.
While the 25 Politburo members are already considered state leaders, those also appointed regional party chiefs or ministers enjoy higher status and more influence than their peers, with unchecked powers.
This probably explains why all three Politburo members ousted since 1989 had been regional leaders. A few other Politburo members appointed as regional party bosses have avoided the dramatic falls suffered by Bo and the two Chens - but they still raise eyebrows for seeming to run their turf as personal empires.
An example is former Tianjin party boss Zhang Lichang, who, with his family, was believed to be involved in a massive corruption scandal which brought down a large number of Tianjin officials. Zhang quit politics in a dignified manner, though, leaving the Politburo at the 17th party congress in 2007 during a major reshuffle. In 2008, Zhang died of an unspecified illness, rumoured to be cancer, and political observers believe he was spared a political purge because of his illness.
Former Xinjiang party boss Wang Lequan, also a Politburo member, was moved to another post in Beijing after nearly 15 years in Xinjiang. Nicknamed 'the king of Xinjiang' for his iron-fisted rule over the restive region, Wang was not implicated in any corruption scandal but was criticised for fuelling ethnic tension. He was removed in April 2010, months after deadly riots rocked Xinjiang's capital, Urumqi .
Most observers agree that the main reason for Bo's downfall is no different from that of Chen Xitong or Chen Liangyu - the power struggle with regional and central leaders.
Whatever his wrongdoings, Bo's political ambition and his daring to challenge the central leadership marked him out for special attention.
The charismatic and ruthless Bo built a base of popular support - inherited from his father, a hero of the 1949 revolution - even if his policies ran counter to those espoused by party general secretary Hu Jintao and Premier Wen Jiabao. Bo cracked down on gang-related crime and encouraged the recitation of quotes from Mao Zedong, banking on such high-profile moves to earn him a seat on the nine-man Politburo Standing Committee when the Communist Party picked a new set this autumn.
The Bo saga once again reflects a key deficiency of China's political institutions, where new leaders have advanced their political careers not only through administrative channels and their credentials, but also through nepotism and patronage.
On its own, it might not be necessarily problematic to appoint a Politburo member to head a region. However, it becomes problematic when China's political system lacks checks and balances.