Mexico Ruling Party: Rival PRI Candidate a 'Liar' Mexico's presidential front-runner huddled with advisers Thursday to respond to a negative campaign ad by the ruling party that calls him a "liar" and strikes at the heart of a successful message that he produces results. The ad by the National Action Party shows a polluted lake and an unfinished bridge among the list of 608 projects that Enrique Pena Nieto says he completed during his term as the Institutional Revolutionary Party governor of Mexico state. His campaign slogan is "I know how to deliver." "Pena Nieto is a liar," says the ad, which has caused an uproar even though it has yet to be aired. The tone is reminiscent of National Action's 2006 ad campaign that was credited in helping sink then front-runner Andres Manuel Lopez Obrador and win the presidency for Felipe Calderon. Negative campaigning was banned in Mexico's election law in 2007 as a result. Since the ad was first posted on the electoral commission's website earlier this week, the ruling party, known by its Spanish acronym PAN, has come out with more projects that it says Pena Nieto abandoned, including a bus line and a library that is closed. "We want to start a public debate on whether Pena Nieto keeps his word," Roberto Gil, campaign coordinator for PAN presidential candidate Josefina Vazquez Mota, told Mexico's MVS radio. Officials of Pena Nieto's party, known as PRI, dismissed the ad as a dirty war by a desperate candidate. Vazquez Mota trails Pena Nieto by more than 20 points in some polls after making a series of missteps in the first week of the campaign that started March 30. She installed some of Calderon's top advisers Monday in a shake-up of her campaign leadership. Pena Nieto said Thursday he wouldn't dignify the charges with a comment. "I won't be distracted by responding to accusations by other parties," he said in a campaign stop. I don't care what they're saying. But the PRI has spent all week reviewing all of the 608 projects that Pena Nieto said he completed as governor of Mexico's most populous state from 2005 to 2011. Campaign officials canceled appointments and met more than half the day Thursday, in part to prepare for a news conference on Friday denouncing the ad. Lopez Obrador was criticized in 2006 from not responding to Calderon's ads that compared him to Venezuelan President Hugo Chavez and called him "a danger for Mexico." His lead of more than 10 points started to evaporate after the ad aired and Calderon, whom no one had expected to win, took the election by about a half percentage point. PRI spokesman Eduardo Sanchez said the party would file a complaint with the electoral commission over the ad. "This is a negative campaign that is prohibited under the law because it is slanderous and libelous," Sanchez said. What they're saying is lies.