Peña Nieto has faced a dip in polling numbers as of late, but that's not directly due to maneuvers by the candidates. It's been because of outside factors, most notably a student movement that gained ground exactly a month ago today, opposing the comeback of the PRI.
As Peña Nieto's polling numbers have gone down since students took to the streets – those of Lopez Obrador's have gone up. Lopez Obrador almost won the presidential race in 2006 (he lost to President Felipe Calderon of the PAN, who is constitutionally barred from running again), and his biggest handicap has been his radicalization after losing that race. He refused to recognize the results and named himself the legitimate president of the country. He has also been painted as a “danger” to Mexico. Ahead of the 2006 race conservatives in the nation sought to paint him as Venezuela's radical Hugo Chavez.
But instead of attacking Peña Nieto, he presented himself as a statesman. He never once got riled. He never made a low blow. He named specifically who would be part of his cabinet before his time ran out. It was as if he was presenting himself as the frontrunner, said political analyst Jose Antonio Crespo, on the after-debate show on Canal 11, one of Mexico's most popular television stations.