MEXICO CITY — Facing a bloody drug war and lackluster economic growth, millions of Mexicans voted Sunday for a president in an election that surveys suggested may bring back a party that had ruled autocratically for much of the 20th century.

No one issue has dominated the campaign, not the more than 50,000 killed in recent years in the efforts to control drug trafficking or an economy that is growing but leaving behind the poor and failing to raise wages.

Instead, pollsters said voters felt a general malaise and fatigue after 12 years of rule by the conservative National Action Party, which had thrown out the centrist Institutional Revolutionary Party, known as the PRI, in 2000 in the first real democratic election here.

The possible return of the PRI shows the disenchantment many Mexicans feel toward the post-PRI leadership. The explosion of drug-related violence over the past few years is high on the list of concerns, of course, for Mexicans and U.S. policymakers, who say they expect to work closely with the next president to strengthen justice institutions and reduce crime. But voters are equally or more focused on the economy.

Some voters said Sunday that they favored the PRI out of tradition or a sense of nostalgia for what they remembered as a more stable time.

“Better the old one you know than the new to get to know,” Jorge Osorio, 70, said, recalling the words of his grandfather as he voted at a poll near Mexico City for the PRI candidate, Enrique Pena Nieto.

Such is the taint of Pena Nieto’s PRI party, which had stayed in power for years through rigged elections, corruption and patronage, that people were reluctant to admit they had supported him. Leonor Acosta Chavira, 77, who waited to vote with some 300 people in Tijuana, said he was worried that others would get angry if they knew of his choice.

“I vote for the party no matter the candidate,” he said.

But others — and many declined to divulge their choice because of government admonishments for “voto secreto” — said they could not give the PRI another chance.

“The PRI had its opportunity for 70 years, and the country didn’t progress,” said Moises Basilio, 29, of Guerrero state and a supporter of the left-leaning candidate, Andres Manuel Lopez Obrador, who narrowly lost in 2006. “We’re a country with great potential — the problem is the government has never made the people a priority.”

Liliana Patino, 33, a voter in Ciudad Nezahualcoyotl just outside Mexico City, backed Josefina Vazquez Mota, the incumbent party candidate, because “I wanted to give them more time to complete what they started.”

Nearly 80 million Mexicans were eligible to vote, with turnout traditionally running about 60 percent.

There were sporadic reports of long lines at polling stations and some that opened late because they were not ready, while watchdog groups were collecting reports of vote-buying and other irregularities.

Osorio found that his name was already crossed off a list of voters when he arrived at his polling station, even though he had not cast a ballot. Polling workers decided it was an error and let him vote.

All the parties have been accused of providing money and other goods in exchange for support, but the PRI has a reputation for being particularly adept at it.

During the PRI’s rule, its leaders were credited with modernizing the economy and creating lasting social programs — the poet Octavio Paz called them “philanthropic ogres” — but they stifled political dissent, rigged elections and economic crises and corruption scandals eventually lead to its downfall.

Now, with Pena Nieto, 45, a youthful, well-spoken candidate tailor-made for — and some say, by — television, the PRI is heavily favored to win, based on most polls that have given him a comfortable margin for the last two years. Political analysts said the party was also expected to make gains in congressional elections.

Vazquez Mota, 51, the National Action Party’s candidate, sought to be Mexico’s first woman president, but her struggle to find a message and awkward moments — in the closing days she suggested women withhold sexual relations with their partners if they did not vote — sunk her into third place in most polls.

Lopez Obrador, 58, of the left-leaning Party of the Democratic Revolution, narrowly lost the race in 2006 and moved into second place, hoping to capture the anti-PRI vote with blistering attacks on the party and Pena Nieto.

A former Mexico City mayor, he draws heavy support in the capital and sought to counter the PRI’s control of 20 of 31 states by campaigning in every one of them.

“The PRI control in the provinces is terrible,” said Sergio Salas, 41, a Lopez Obrador supporter in a Mexico City middle-class district. “That’s where the secret is.”

Pena Nieto, who cast himself in the mold of pragmatic, economic reformers of the past, campaigned largely on change and promises to increase jobs and wages, while vowing to refocus the drug war on reducing murder, kidnapping, extortion and other violent crime afflicting Mexicans.

He scarcely mentioned the hunt for cartel leaders and reducing drug trafficking, raising worries in Washington about his commitment to the drug fight, but said he would keep the military on the streets and sent reassurances to Washington that he would continue to work closely with U.S. law enforcement.

He remained ahead of his opponents, even as they unleashed a series of attacks on his party, suggesting it would make deals with the cartels to bring peace rule by corruption and patronage, as it had in the past.

University students held demonstrations against him and the major television networks, accusing them of biased coverage and taking aim in particular at Televisa, the largest, on which he has frequently appeared in advertisements, infomercials and news coverage. Pena Nieto is married to one of the network’s most popular soap opera stars and she campaigned prominently for him.