Enrique Pena Nieto has claimed victory in Mexico's presidential election.

Nieto now faces an uphill task because of corruption allegations, drug violence and sluggish economy.

Analysts say three factors helped Nieto succeed in the election.

Mexican presidential candidate for Mexico's Institutional Revolutionary Party (PRI), Enrique Pe Nieto, shows his marked thumbs after casting his vote in Atlacomulco, State of Mexico, Mexico, on July 1, 2012. Mexican voters started casting their ballots Sunday morning to choose the country's next president, 500 deputies and 128 senators in the presidential and congressional elections. (Xinhua/David de la Paz)

Enrique Pena Nieto has claimed victory in Mexico's presidential election and now faces an uphill task because of corruption allegations, drug violence and the country's sluggish economy.

Nieto, representing the Institutional Revolutionary Party (PRI), the longest ruling party in Mexico during the 20th century, won nearly 38.55 percent of Sunday's vote. That was a margin of about six percentage points over his nearest rival, according to a "quick count" by election authorities.

Andres Manuel Lopez Obrador of the Democratic Revolution Party (PRD) finished second with about 31 percent of the vote while Josefina Vazquez Mota of the ruling National Action Party (PAN) placed third with 25 percent.

A fourth candidate, Gabriel Quadri de la Torre of the New Alliance Party (Panal), earned around 2 percent of the vote.

Analysts say three factors helped Nieto succeed in the election.

First, as governor of Mexico State since 2005, Nieto has won widespread for his heavy investment in public works and for the headway he made in reforming health, education and the fight against poverty.

The sound organizational structure of the PRI, which ruled Mexico for 71 years until it was voted out in 2000 due to rampant corruption and bureaucratic excess, also benefited its telegenic front man.

Secondly, Nieto persuaded many Mexicans that his government would better cope with the many challenges facing Mexico, including an economic recession, soaring prices, high unemployment, and poverty.

An effective campaigner, Nieto promised to make "change" in Mexico with a series of policies to support businesses, reduce poverty, increase education investment, and promote employment.

Thirdly, Nieto convinced voters that he would advance an effective new strategy against drug crime to restore social order in Mexico. Outgoing President Felipe Calderon's war against organized crime achieved limited success and was unable to stem the drug-related violence that left as many as 60,000 people dead.

Some observers say that a split within the ruling PAN party also helped Nieto. Former President Vicente Fox, a PAN veteran, criticized the current government for its ineffective economic and social policies and urged PAN supporters to back the candidate with the greatest chance of winning -- in other words, Nieto.

ROAD AHEAD UNEVEN

With Nieto claiming a clear victory, Mexico's presidential election completed a dramatic comeback for the PRI, which had been out of office for 12 years. However, analysts say the 45-year-old president-elect is facing an uneven road ahead.

Boosting economic growth could be the biggest challenge for Nieto, who promised voters to promote economic and social reform. But if Mexico's economy doesn't improve and people's livelihoods show no immediate improvement, then the PRI's ruling foundation could be in trouble.

Nieto also faces stiff pressure to eradicate corruption and bribery within his own party, notorious for corruption and collusion with drug cartels. If the president-elect tries to fulfill his campaign promises, he will have to manage drastic reforms and risk splits in his own party.

How to launch a new and better drug control strategy is also a question that will test Nieto's wit and character.

Calderon's drug war dissatisfied Mexicans but was favored by Washington, which provides 400 million U.S. dollars a year in aid to cut the drug trafficking channel from Latin America to the U.S.

Local media said that Washington did not want to see the PRI return to power due to some party members' close ties with the drug cartels. Even though Nieto has vowed to restore social order, he has yet to explain his specific measures.