MEXICO CITY — Nearly two months remain before Mexico picks a new president, but it’s increasingly difficult to envision a winner not named Enrique Peña Nieto.

Peña Nieto, a former governor of Mexico state, the nation’s most populous, has led all major polls, some by 20 points or more. This week, he emerged mainly unscathed from a presidential debate that foes had framed as a high-stakes showdown.

Opponents entered Sunday’s debate hoping for a game-changing gaffe by Peña Nieto. He has largely avoided unscripted public remarks since drawing widespread ridicule late last year when he was unable to name three books that had influenced his life and then could not cite the price of a kilo of tortillas or say how much the minimum wage was.

But there was no such stumble this time by the candidate of the once-ruling Institutional Revolutionary Party, or PRI. Rather, he appeared to successfully blunt a flurry of jabs by his two main foes: Josefina Vazquez Mota of the ruling National Action Party, or PAN, and Andres Manuel Lopez Obrador of the left-leaning Democratic Revolution Party, or PRD. Instant polls showed that many viewers deemed Peña Nieto the winner.

One more debate is planned before voters go to the polls July 1, giving opponents what may be a last chance to turn the momentum. But many analysts are concluding that, barring an unexpected big event, the only real drama left for election day is whether Peña Nieto can carry his party to a majority in Congress.

Peña Nieto, 45, backed by the country’s dominant television network, portrays himself as an agent of change. He has profited from a disciplined campaign, weaker-than-expected competition and broad dissatisfaction over runaway violence and stubborn unemployment under President Felipe Calderon, of the right-of-center PAN.

Analysts say Peña Nieto is running well among independent and middle-class voters, boasts support across gender and age lines and is competitive even in regions where the PAN once dominated, such as northern Mexico.

“He’s looking very strong, almost on all fronts,” said Carlos Ramirez, a Mexico analyst for the New York-based Eurasia Group. “It’s going to be very difficult for someone to overcome Peña.”

Still, Ramirez noted that many voters have yet to make up their minds. In a campaign that has mostly generated the blahs, as many as 3 in 10 voters have yet to settle on a choice. Young voters, many of whom say they are unhappy with all the ballot options, could prove a wild card.

But even undecided voters may not offer much hope for Vazquez Mota or Lopez Obrador, who are locked in a battle for second place, according to polls. Many undecided voters may stay home. And some surveys put Peña Nieto well ahead even among those who say they haven’t made a final decision.

So what could change the outlook in coming weeks?

The arrest of a ranking PRI figure — a current or former governor, for example — could hurt Peña Nieto. Many people are watching to see whether dual scandals in the northern state of Coahuila — one over public borrowing, the other involving money-laundering allegations against a former treasurer — ensnare an ex-governor, Humberto Moreira, who served as the party’s president before stepping down in December.

The capture of the country’s most wanted drug fugitive, Joaquin “Chapo” Guzman, would boost Calderon and, by extension, his party’s candidate, Vazquez Mota.

“Any drama will have to come from external factors, actions by the government or events relating to public safety — something from the outside,” said Jorge Buendia, a pollster and analyst in Mexico City. “Peña is a very disciplined candidate. He’s unlikely to make mistakes.”

It seems certain Peña Nieto’s rivals will step up they type of attacks seen in Sunday’s debate, whose main stars were an obscure fourth-party candidate named Gabriel Quadri and a bosomy hostess whose low-cut white dress set the blogosphere afire.

Lopez Obrador sought to evoke the PRI’s legacy of graft by linking Peña Nieto to Arturo Montiel, an earlier governor of Mexico state who was the subject of a corruption investigation but cleared. For her part, Vazquez Mota took aim at Peña Nieto’s stewardship as governor, saying his state lagged when it came to competitiveness and open government.

Peña Nieto struck back by citing a bribery scandal during Lopez Obrador’s tenure as mayor of Mexico City that sent two mayoral aides to prison. And he said Vazquez Mota was chronically absent as a member of Congress’ lower house, the Chamber of Deputies.

The candidates were back on the campaign trail this week, and there was a growing sense that Peña Nieto’s rivals were now also battling the clock.

ken.ellingwood@latimes.com