Mexico's presidential election tainted by claims of vote buying That is the suspicion emerging here, in the days after preliminary vote tallies by Mexico's Federal Election Institute (IFE) gave Enrique Peña Nieto a 6 percentage point win over second-place finisher Andres Manuel Lopez Obrador, who represents the country's left. The initial count shows Peña Nieto's margin of victory Sunday was more than 3 million votes, an advantage that should be wide enough to overcome any legal challenge to his win, including Lopez Obrador's demand for a full recount of the ballots. President Obama and other leaders called to congratulate Peña Nieto on his victory on Sunday night. He has been declared the "virtual president" in the Mexican press and has been busy giving speeches laying out an ambitious agenda. Final results are due by Sunday. But the whiff of suspicion building over Peña Nieto's win has less to do with the overall vote tally than the way Mexico's presidency was won. Peña Nieto campaigned on a promise to break with the heavy hand and dirty tricks associated with his Institutional Revolutionary Party (PRI). But it appears that some of his party's crafty operatives may have been working with the old PRI playbook. PRI activists allegedly handed out pre-paid gift cards from the grocery chain Soriana to voters in some districts, according to amateur videos broadcast Wednesday on Mexican television networks. The alleged card recipients mobbed at least one store on the outskirts of Mexico City in a panic after rumors spread the cards would be invalidated. According to the Associated Press, the cards were each worth 100 pesos, about $7.50. "It was neither a clean nor fair election," said Eduardo Huchim of the Mexican watchdog group Civic Alliance, which is funded by the United Nations Development Program. This was illegal bribery on a vast scale, said Huchim, a former IFE official. It was perhaps the biggest operation of vote-buying and coercion in the county's history. But even Huchim acknowledged the vote buying and coercion his group is alleging will not change the election's outcome. It's not against the law in Mexico for political parties to give out gifts -- such as school supplies, a sack of cement, a hot lunch, or even pre-paid gift card -- and in fact is common practice among all three major parties, in national, state and municipal elections. The costs of the gifts must be reported to election officials, and total spending cannot exceed campaign limits. Violations are fined, after the fact, and campaigns routinely consider the fines the cost of getting electing. However, it is illegal to directly buy votes with gifts. Critics could not say how many prepaid gift cards were distributed in this election. The Civic Alliance also said that the PRI employed child lookouts as young as eight years old. Called "niños halcones" or "kiddie hawks," they were allegedly sent to some polling stations to guarantee voters marked their ballots as they were paid to do. The group based its accusation on their own observations at 170 polling stations where they detected a dozen cases where children spying on voters. Peña Nieto said the election was not stolen, and that the PRI did not buy a single vote. But the president-elect and his party are more focused on the vote count, and not on allegations of vote buying and coercion. "We are calm because we won the election, and if we recount the votes, we will win again," said Luis Videgaray, a top campaign official for Peña Nieto. Videgaray said Lopez Obrador and other critics "should stop fighting the arithmetic." A partial recount of at least one-third of the ballots is underway, and IFE said it is looking into the fraud allegations. Mexico's ruling National Action (PAN) party has not challenged the results, but the Lopez Obrador campaign said it detected irregularities at 114,000 of the country's 143,000 polling stations, and was amassing evidence of widespread vote-buying and other forms of cheating. "This election was a national embarrassment," said Lopez Obrador. Lopez Obrador also claimed he was cheated out of the presidency in 2006, when he lost to Calderon by half a percentage point. His protesters launched demonstrations that carried on for months. The controversy over allegations of vote buying undermines the narrative that Peña Nieto has been pushing that he belongs to to a new generation, honest, transparent, who renounced the coercion, threats and dirty tricks of their elders, known to Mexicans as "the dinosaurs" of the old PRI, the hacks who delivered the vote and kept people in line. "If Lopez Obrador can prove that PRI engaged in serious and systematic buying and coercion of the vote, then it would call into question the validity of the results -- no matter what the vote count is," said Eric Olson, associate director at the Mexican Institute of the Woodrow Wilson Center in Washington, who is in Mexico City monitoring the election.