The steady but sure fragmentation of Mexico’s political opposition is increasing the likelihood of the federally ruling Partido Revolucionario Institucional (PRI) retaining power in the presidential election on 1 July 2018, despite a succession of opinion polls showing that President Enrique Peña Nieto is the least popular head of state since records began. In the latest boost to the PRI’s prospects, Margarita Zavala, one of the favourites to win the presidency, abandoned Mexico’s main opposition Partido Acción Nacional (PAN) to pursue election as an independent after her public disagreements with the party president, Ricardo Anaya, proved insoluble.