| ORIZABA, Mexico
ORIZABA, Mexico Six years after Andres Manuel Lopez Obrador watched his big lead for the presidency evaporate in the final weeks of the campaign, the leftist is now gaining ground in polls and hopes to snatch a last-minute victory in the July 1 election.
Fueled by a sudden surge in youth opposition to his main rival, the 58-year-old Lopez Obrador has narrowed the gap on front-runner Enrique Pena Nieto of the opposition Institutional Revolutionary Party (PRI).
He has capitalized on student protests against the PRI, which ruled Mexico for seven decades before it was voted out of power in 2000, and has a new confidence on the campaign trail.
Most polls still show Pena Nieto with a double-digit lead but Lopez Obrador's pledges to introduce a national old age pension and construction programs to stimulate economic growth have found more support among the 58 million Mexicans - about half the population - living on less than 2,100 pesos ($150) a month.
"Our rivals are getting nervous. The soap opera has finished and the PRI will lose the presidential election," Lopez Obrador said this week at a campaign rally in the eastern city of Orizaba in Veracruz state, a PRI stronghold.
Known as "El Peje," a type of swamp fish in his native Tabasco, Lopez Obrador has focused his most recent campaigning in Mexico's poorer center and south, where he challenges the traditional base of the PRI.
About 10,000 people turned out in Orizaba to see the former mayor of Mexico City promise to revive the impoverished countryside and install an austere, hard-working cabinet inspired by what he said was the honesty of indigenous villages across Mexico.
"We are fed up of the same people in power. We need a different approach," said Rene Yopihua, a farmer who had come in from the village of Tuxpanguillo to see Lopez Obrador.
The fiery leftist candidate has kept up a relentless schedule since his 2006 loss to Felipe Calderon of the conservative National Action Party (PAN).
He said he was the victim of electoral fraud and launched weeks of disruptive protests in the capital, blockading parts of the city center. He then embarked on a long tour of the country with his campaign saying he has visited Mexico's 2,500-odd municipalities at least twice on average.
But the 2006 protests hurt his popularity and until recently he was stuck in third place, over 20 points adrift of Pena Nieto, a telegenic 45-year-old married to a soap opera star.
Over the past month, that gap has narrowed.
Most polls still show Lopez Obrador at least 10 percentage points behind Pena Nieto but one survey last week put him just four points back. This week Lopez Obrador even said he had overtaken the PRI candidate in an undisclosed poll.
Beginning his career at a state institute for indigenous people in Tabasco in the 1970s, Lopez Obrador has long styled himself as a defender of the downtrodden and the oppressed.
On stage in Orizaba, he was surrounded by supporters in traditional indigenous dress and he refused an umbrella when rain poured down, soaking himself along with the crowd.
"They say cynically that in Mexico only the corrupt get ahead. But this dishonesty will go into the trash heap of history," he said. "The budget belongs to the people."
His campaign has been aided by several corruption scandals involving the PRI, including an investigation into a former governor of Tamaulipas state on suspicion of money laundering and taking cash from drug gangs.
The silver-haired Lopez Obrador has a fiercely loyal support base and is in his element giving passionate speeches.
But he is not a polished performer in debates and struggles to face down accusations he is hot-headed and intolerant.
A new campaign ad by the PAN calls Lopez Obrador "a danger to Mexico" and compares him to Venezuelan leader Hugo Chavez. That tactic was very effective in 2006 when Lopez Obrador led for most of the campaign but ended up losing by less than 1 percentage point to Calderon.
During a political discussion aired this week by Televisa, Mexico's dominant broadcaster, a panel of journalists grilled Lopez Obrador on whether he believed in Mexico's democratic institutions, including the Federal Electoral Institute, which oversees the elections.
"I trust the Mexican citizens," was his reply.
Such comments turn off some voters who have not forgotten the chaos caused by his blockades and demonstrations.
"Lopez Obrador just creates more problems. I saw people lose their jobs last time the city center was blocked by his protests," said Mexico City resident Joaquin Segura, who plans to vote for Pena Nieto.
To win, Lopez Obrador must convince undecided voters, who some polls show to be as much as 18 percent of the total.
But he will struggle unless he can convert his appeal on the campaign trail into success in TV interviews and the final televised debate, which will take place on Sunday.
In that showdown, Lopez Obrador will likely come under fire from both Pena Nieto and PAN candidate Josefina Vazquez Mota, who is now trailing in third place in most polls.
"There are two sides to Lopez Obrador which can emerge, and it is not clear which one will come out," said Rodrigo Aguilera, Mexico analyst for the Economist Intelligence Unit. "You can see him be concise and articulate, or he can come out as defensive and fumbling."
Student agitation against the PRI and Pena Nieto have given Lopez Obrador some hope. Mexicans still have vivid memories of PRI rule between 1929 and 2000 and the allegations of corruption, election-rigging and violent repression of dissent.
In 2000, the PRI was ousted by the PAN, but a surge in drug-related killings under Calderon and weak job growth have allowed the old rulers to mount a strong comeback.
That momentum was jolted after a group of students heckled Pena Nieto over his record as governor of the State of Mexico during a visit to a Mexico City university last month.
With abuse ringing in his ears, Pena Nieto made a hurried exit from the Ibero-American University and the incident sparked a wave of online activism against him.
Soon afterwards, thousands marched in Mexico City to protest against the PRI, and booing has broken out in cinemas in parts of the capital when advertisements for Pena Nieto are shown.
More online criticism of Pena Nieto followed on Thursday, after British daily The Guardian said it had acquired documents that appeared to show that Televisa had helped to raise the PRI politician's national profile and had worked to sabotage Lopez Obrador's 2006 bid.
Televisa rejected the allegations and demanded a public apology from the newspaper, whose report attracted a massive amount of attention on online social media.
The claims, which follow other reports alleging close ties between Pena Nieto and Televisa, could feature prominently in Sunday's televised debate, which the broadcaster is airing. The PRI denied Pena Nieto had any such deal with Televisa.
Lopez Obrador on Friday morning urged the broadcaster and Pena Nieto to clarify their relationship, which student protesters have criticized during the campaign.
While the student leaders say they are independent, Lopez Obrador has championed their cause. He now opens his events with young speakers, who he calls the "yeast of his movement."
Cristian Garrido, a student in Orizaba, took part in anti-PRI protests and came out in support of Lopez Obrador.
"Pena Nieto only helps the upper class but he would do nothing for those below," said Garrido, 20. "We could see a much better Mexico if Lopez Obrador wins."
Nevertheless, some polling experts say the significance of the anti-PRI youth vote should not be overstated.
"The students involved in these demonstrations have had a big impact in the media," pollster Jorge Buendia said. "But these students are not a really significant number of voters."
(Editing by Kieran Murray and Eric Beech)