By Dave Graham
MEXICO CITY (Reuters) - Mexico's presidential hopefuls square off in a televised debate on Sunday with the trailing candidates seeking to land heavy blows against hot favorite Enrique Pena Nieto to spoil his chances of victory in the July 1 election.
Polls show Pena Nieto, of the opposition Institutional Revolutionary Party (PRI), is heading for a comfortable victory, and could capture as many votes as his two main rivals combined.
Though the gap has lately narrowed slightly, second-placed Josefina Vazquez Mota of the ruling conservative National Action Party (PAN) and leftist Andres Manuel Lopez Obrador, the 2006 runner-up, are running out of time to catch up with Pena Nieto.
After a number of embarrassing public gaffes at the turn of the year, Pena Nieto has ducked several invitations to debate with his rivals, prompting accusations from critics that he cannot think on his feet and will be vulnerable on Sunday.
However, his campaign has been preparing the telegenic 45-year-old for the contest, and the planned questions have already been published by electoral authorities.
"If Pena Nieto doesn't lose or mess up in a big way, then the debate will be a success for him," said Jorge Buendia, director of polling firm Buendia & Laredo.
Since the election campaign began some five weeks ago, opinion polla have shown Pena Nieto could win close to 50 percent of the vote in the presidential contest, sweeping the PRI back to power 12 years after it was ousted by the PAN.
The handsome former governor of the State of Mexico, a populous region flanking the capital, built up a reputation for efficiency with a series of public works he pledged and checked off during his 2005-2011 administration.
His PRI governed Latin America's second biggest economy for 71 years until 2000, though the final decades were marred by frequent accusations of misrule and authoritarianism.
Vazquez Mota's campaign has sought to brand Pena Nieto as a liar who did not keep his pledges, and has wasted no opportunity to suggest the PRI is complicit with criminal gangs, which have menaced the country under President Felipe Calderon.
Calderon sought to bring Mexico's drug gangs to heel by sending in the army after he took office in December 2006, but violence has spiraled since then, damaging support for the PAN.
The Mexican constitution does not allow the president to seek a second term.
All the candidates have promised to restore peace to Mexico, and create more jobs for the country's growing population, issues that will feature prominently in the two hour debate.
ELEPHANT IN ROOM
The showdown also features a fourth candidate, Gabriel Quadri of the New Alliance Party, a group with strong ties to the powerful teachers' union in Mexico. Though polls give him no hope of winning the presidency, he could stir up trouble for other candidates if he goes on the attack.
Voters have paid little heed to attacks on the PRI, which has tried to stay aloof from the fray. Instead, it has spread a message that it is the only party with the experience to revive the economy and put a stop to the violence plaguing Mexico.
For the debate, the PRI has managed expectations by doing little to dispel claims that Pena Nieto is "just a pretty boy with an empty head" who relies on a teleprompter, said Federico Estevez, a political scientist at the private ITAM University.
"Which means that heading into the debate, I think all Pena Nieto has to do is hold his own," said Estevez.
Rivals say Pena Nieto's popularity owes a lot to his productive relationship with dominant broadcaster Televisa, which will air the debate from 8 p.m. (9 p.m. EDT/0100 GMT on Monday).
Even if he does slip up, it may not cost him dearly.
A recent survey by polling firm Consulta Mitofsky showed only about a third of voters said they were interested in the debate, which will be followed by another next month.
Mexico's other main television network, TV Azteca, may have helped to further underplay the debate's impact by deciding to broadcast a top flight soccer match during the exchange.
And far from being just a potential trap for Pena Nieto, the debate is a chance for Lopez Obrador to challenge Vazquez Mota for second place in the race, said pollster Buendia.
"They haven't really attacked the government yet and this is the elephant in the room. They can criticize the poor economic performance and the growing wave of violence," he said.
Polls have shown Lopez Obrador closing on Vazquez Mota and the passionate orator could offer some of the liveliest attacks on rivals during the exchanges, said Estevez at ITAM.
(Additional reporting by Mica Rosenberg, Lorne Matalon and Ioan Grillo; Editing by Sandra Maler)