Just weeks before Nepal erupted in flames this month, India had invited the Nepali prime minister to New Delhi on a state visit, partly to smooth over testy ties between the South Asian neighbors. The prime minister, K.P. A similar uprising in Bangladesh last year upended the authoritarian government of Sheikh Hasina. Such instability across South Asia distracts India from focusing on its ambition to be a global superpower. But India cannot leave things unattended in its own backyard.