HONG KONG — China’s president, Xi Jinping, is about to plunge the country and himself into a risky experiment: an attempt to carry out market-driven economic overhauls while reinforcing the Communist Party’s pillars of political and ideological control. This mixed agenda has magnified doubts about whether he can deliver on his promises of transformation. At a meeting, or plenum, of the party’s Central Committee that starts Saturday, Mr. Xi will enumerate his plans for an economic overhaul, and state-run news media has promoted the event as a turning point. Mr. Xi and Prime Minister Li Keqiang have indicated that they want to nurture healthy, sustained growth by encouraging more market competition, private business, financial liberalization and individual consumption, leaning away from the state-focused policies of the past decade. Yet, Mr. Xi wants to achieve this economic shift away from the state while strengthening the ruling party , which derives […]