The fiesta is over. Mexico, a remarkably important nation of some 120 million people—indeed, the world’s fifteenth largest economy—is descending into crisis. Students have been slaughtered en masse with the complicity of a corrupt police force. The country’s young president and his finance minster are embroiled in a corruption scandal. And the recent fall in oil prices—which looks set to continue—only portends further suffering.

It wasn’t supposed to be this way. When 48-year-old Enrique Peña Nieto was elected Mexican president in 2012, his country’s future looked bright. A self-styled reformer, the leader of the Institutional Revolutionary Party (PRI) and former governor of Mexico State moved immediately to implement his Pact for Mexico, which called for the achievement of some 95 goals over his six-year term.