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.