Zhou's time as the top official in Sichuan, the oil sector, and Public Security Minister earned him significant leadership experience and personal clout, as well as a complex network of patronage. In 2007, Zhou was transferred to fill the vacancy from Luo Gan, who retired from his leadership position as central Zhengfawei chief. With this powerful position, Zhou also gained a spot on the Politburo Standing Committee, the highest council of Communist Party rulers. With the expansion of Zhengfawei authority in the preceding years, Zhou became the top official responsible for China's courts, law enforcement, prosecution agencies, paramilitary forces, and domestic intelligence agencies. Even though he was ranked ninth in the party leadership hierarchy, Zhou, dubbed China's "security tsar" by select English-language media, emerged as one of the Standing Committee's most important members, and one of China's most powerful men.