The Vietnamese Communist Party says President To Lam on Thursday became the caretaker of the Party while its general secretary Nguyen Phu Trong focuses on receiving treatment for his health. Trong, who has been Vietnam's most powerful politician since 2011, is an ideologue who views corruption as the biggest threat to the party. As Vietnam's top security official, Lam led a sweeping anti-graft campaign until he became the president in May.