(The change in Sri Lanka) marks the third big Asian election in the last 12 months in which voters have installed a new leader: first in India, where Prime Minister Narendra Modi thumped the incumbent Congress Party; then Indonesia, where Joko Widodo, an outsider, won over voters with his record of competence as governor of Jakarta; and now Maithripala Sirisena’s upset victory in Sri Lanka. That kind of turnover at the top must give pause to China’s Communist Party leaders, who see the mandate of heaven as an institutional birthright.