Mexico Could Return Old Ruling Party to Power A single party dominated Mexico for most of the past century, and its loss 12 years ago proved to many that the country was finally a democracy. Now the nation's voters seem ready to bring it back to power in Sunday's presidential election. The Institutional Revolutionary Party, led by telegenic former Mexico State Gov. Enrique Pena Nieto, has held a strong lead throughout the campaign, and also seems poised to retake at least a plurality in Congress. The party has been bolstered by voter fatigue with a sluggish economy and the sharp escalation of a drug war that has killed roughly 50,000 Mexicans over the past six years. The desire for change suddenly works to benefit the party known as the PRI that ran Mexico from 1929 to 2000. Hoping for a shocking upset are leftist Andres Manuel Lopez Obrador, whose narrow loss in Mexico's last election led to charges of voter fraud and weeks of massive protests, and the candidate of the ruling National Action Party, Josefina Vazquez Mota, the first woman ever nominated for the presidency by a major party in Mexico. It would be a once-unthinkable comeback for the PRI, which many believed was doomed after its 2000 loss and which was still reeling in the last presidential election, when it finished a weak third. Election worker Ninel Ramirez Torillo shows a box that will be used to hold ballots for the upcoming presidential election in Mexico City, Saturday, June 30, 2012. Mexico will hold general elections, including the presidential election, on July 1. (AP Photo/Marco Ugarte) Close Pena Nieto has cast himself as a pragmatic economic moderate in the tradition of the last three PRI presidents of the 20th century. He has called for greater private investment in Mexico's state-controlled oil industry, and has said he will try to reduce violence by attacking crimes that hurt ordinary citizens while deemphasizing the pursuit of drug kingpins. All of the parties are accusing rivals of emulating the traditional PRI tactic of offering voters money, food or benefits in return for votes. Lopez Obrador's Democratic Revolution Party says Pena Nieto's campaign has handed supporters prepaid money cards worth nearly $5.2 million (71 million pesos). PRI activists have published photographs of truckloads of handouts it said were given out by Democratic Revolution backers. But electoral officials have repeatedly insisted that outright fraud is almost impossible under the country's elaborate, costly electoral machinery. The government also promises efforts to avoid outbursts of violence linked to the country's endemic drug gang violence. Military and civilian officials announced that the army would step up election day patrols in the border city of Nuevo Laredo, where a bomb in a pickup truck exploded outside city hall on Friday. The 45-year-old Pena Nieto, who is married to a soap opera star, also has been dogged by allegations that he overspent his $330 million campaign funding limit and has received favorable coverage from Mexico's television giant, Televisa. University students launched a series of anti-Pena Nieto marches in the final weeks of the campaign, arguing that his party hasn't changed since its days in power. Pena Nieto says his party has abandoned the heavy-handed ways of the past and will govern in an open and pluralistic manner, and many say the PRI would not be able to reimpose its once near-total control even if it wanted to because of changes in society, the judiciary and Congress.