From Sebastian Veg, Research Professor at the School of Advanced Studies in Social Science in Paris:
By shaking up the unwritten rules that have prevailed since Deng Xiaoping consolidated power, Xi is taking a political risk. In exchange for the immunity that PBSC members were granted, they were expected to retire at the end of their term, and to remain loyal to collective decisions. If immunity is denied, both of these tenets may begin to be questioned. Why should powerful leaders retire if they can then be targeted? Why should they accept decision by consensus if they can later be made to pay the consequences as is alleged in Zhou’s case with the vote on Bo? They may be better off spending their terms gathering compromising material on other colleagues. Xi no doubt understands the risk, and believes it must be taken because the Party’s legitimacy is in danger. However, by disturbing the carefully crafted institutional balance, he runs the risk of overplaying his hand.
Read more at For Chinese Power Game, a Changing Equation.