Earlier this year, the triumph of Enrique Pena Nieto in Mexico's presidential race seemed inevitable. He represents the Institutional Revolutionary Party, or PRI, who ruled the country for more than 70 years before they lost power in 2000. Many Mexicans are fed up of the ongoing drug war and of the incumbent PAN party that started it. But the birth of a student pressure group has thrown the PRI's return to the presidency into question. Duration: 02:26