© Claudia Daut / ReutersAn electoral worker carries a sealed ballot box for a recount of votes at a district office of the Federal Electoral Institute in Mexico City on Wednesday.
"I am totally, totally certain that the party acted within the law," Enrique Pena Nieto of the Institutional Revolutionary Party, or PRI, told a journalist from BBC News on Wednesday.
Leftist runner-up Andres Manuel Lopez Obrador has refused to concede and demanded a new tally, alleging vote-buying and coercion by the PRI, whose seven decades of rule until it lost power in 2000 were marked by widespread allegations of vote-rigging.
Preliminary results of the presidential vote showed Pena Nieto had officially won more than 38 percent of the vote, 6.5 points clear of Lopez Obrador.
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Mexico's election officials on Wednesday recounted votes from more than half the polling booths in the presidential and congressional elections.
While the PRI declared the vote had been fair, some observers said it most definitely had not been.
"It was neither a clean nor fair election," Eduardo Huchim of the Civic Alliance, a group funded by the United Nations Development Program, told The Washington Post.
The vote-buying was bribery on a vast scale, Huchim, a former Mexican elections official, told the newspaper. "It was perhaps the biggest operation of vote-buying and coercion in the country's history," he said.
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Huchim said that the coercion his group alleged would not change the election's outcome.
Rush to grocery stores
Feeding suspicion of large-scale vote-buying were scenes of thousands of people rushing to grocery stores this week to redeem pre-paid gift cards they said the PRI had given them ahead of the election. Several told reporters they had been told to turn in a photocopy of their voter ID card in order to get the gift cards.
"If they're giving me money, then who isn't going to love them?" an unnamed woman said in one video. "Five hundred pesos is a lot of money!"
(500 pesos = $37.50)
YouTube video allegedly showing women discussing having received supermarket cards from PRI
Under Mexican election law, giving voters gifts is not a crime unless the gift is conditioned on a certain vote or is meant to influence a vote. However, the cost of such gifts must be reported, and cannot exceed campaign spending limits. Violations are usually punished with fines, but generally aren't considered grounds for annulling an election.
Shoppers nearly stripped some shelves at a Soriana store in the poor district of Iztapalapa and officials in Mexico City, which is governed by Lopez Obrador's Democratic Revolution, ordered at least one branch of the chain closed for alleged violation of safety codes.
© Marco Ugarte / APA woman shows her pre-paid gift card while waiting in line at a Soriana supermarket in Mexico City on Tuesday. Many of the people at the supermarket say they went to redeem pre-paid gift cards they said were given them by the party that won Mexico's presidency and at least a few cardholders were angry, complaining they didn't get as much as promised, or that their cards weren't working. The incidents are inflaming accusations that the election was marred by massive vote-buying.
PRI spokesman Eduardo Sanchez said that "Neither the PRI's executive committee, nor Enrique Pena Nieto's campaign has contracted any service from the Soriana grocery store chain.
Asked if some other local or congressional PRI candidate could have done it on behalf of Pena Nieto, he said "I don't know."
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Humberto Fayad, a spokesman for the Soriana chain, denied the company had sold huge amounts of gift cards to the PRI.
"There is no agreement between the PRI and Soriana, or Soriana and any other political party. Soriana is a non-political company," Fayad said.
The PRI, too, accused rivals in many parts of the country of handing out groceries or using government programs to influence voters.
The governing National Action Party accused Pena Nieto's campaign of acquiring about 9,500 prepaid gift cards worth nearly $5.2 million (71 million pesos) to give away for votes. Authorities said a business had bought that number of cards, but that they had found no direct evidence of vote-buying. That investigation continues.
Party's checkered past challenges Mexico's president-elect
Lopez Obrador had asked for a recount of every vote, but the electoral institute said that just over half the polling booths for the presidential race met the necessary conditions set out by a 2007 electoral law.
That law stipulates that a recount can only be requested at a polling station where there is a gap of less than 1 percentage point between the two leading candidates, or for other "inconsistencies" that could include hard-to-read ballots.
The final presidential numbers were due on Thursday.
In 2006, Lopez Obrador demanded a recount after losing to President Felipe Calderon by slightly more than half a percentage point, or some 250,000 votes. This time he finished more than 3 million votes behind Pena Nieto.
Electoral law did not permit a full recount in 2006 and his request was refused. Lopez Obrador then called out his supporters who launched street protests that choked Mexico City for weeks.
Msnbc.com staff, Reuters and The Associated Press contributed to this report.
Comment: It is sad that the elite thinks so little of the people that they are willing to buy their voting rights for 20 silver coins. Even sadder that some are willing to sell them, and thus sell their country - their family, their friends and all they supposedly value - to psychopaths. Can there be any hope for the human race if they give in so easily?