At 76, Nguyen Phu Trong is a man in a hurry, intent on saving Vietnam's Communist Party from corruption, backsliding and irrelevance. The implications for Vietnam are considerable, since the party’s claim on a monopoly of political power largely rests on its presumed moral superiority.

Trong, a Marxist theoretician, is an unlikely leader. For decades, he toiled in obscurity, railing against party members’ loss of Marxist-Leninist virtue and decrying the erosion of the party’s revolutionary legitimacy. Then, three years ago, Trong orchestrated the dismissal of his bete noire, two-term Prime Minister Nguyen Tan Dung. Now he’s head of state as well as party chief, the most powerful Vietnamese leader in decades and the scourge of high officials who have combined with unscrupulous businessmen to rip off the state. ...