And that means that Mr. Peña Nieto remains clearly out in front.
Josefina Vázquez Mota of the ruling National Action Party (PAN) has, according to most polls, been at a distant second throughout the race, and she has focused on undermining Peña Nieto's lead. Ms. Vázquez Mota pulled out an article by The Economist last night that questioned the veracity of statistics on homicides during Peña Nieto's time as governor in the state of Mexico.
She emphasized that as the country's first woman president she would represent a turn towards a more honest and sensitive government.
“I want to be president because I have the sensitivity, as a woman, to listen,” she said.
Andres Manuel Lopez Obrador from the left-leaning Democratic Revolution Party (PRD) also used visual props to attack Peña Nieto, holding up a photo showing him with a former governor whose term ended amid corruption allegations.
The PRI governed Mexico for most of the 20th century until the PAN won the presidency in 2000. All candidates are trying to paint Peña Nieto as a return to an authoritarian past, and Mr. Lopez Obrador added that voting in either the PRI or PAN would not represent true change in the nation.
"This dominant group has privatized the government," Lopez Obrador said. "Do you think things will get better if the PRI comes back? Let's take a totally new path."