MEXICO CITY - Popular pique threatens to hamstring what seemed like Enrique Peña Nieto's predestined path to Mexico's presidency.

With five weeks until the vote, most opinion polls agree that the picture-perfect candidate of the once-monolithic Institutional Revolutionary Party, or PRI, still wields a double-digit lead over his closest rivals.

But student-led protests promoted by tweets, phone texts and Facebook touts have multiplied in Mexico's capital and other cities against Peña, 45, and what many see as the fawning coverage he's receiving in the broadcast media.

"This is an aggression against democracy," sociology student Rogelio Salgado, 23, said Wednesday as he joined some 15,000 young Mexico City marchers in damning both Peña and the media pandering. "We still think there is time to do something. That's why we are here."

'I have memory'

The protests began two weeks ago when jeering students at a pricey, private Mexico City university chased Peña out of a campaign meeting with them.

Protesters have been spurred by corruption allegations against PRI governors and other politicians. And many Mexicans remember other excesses, including the massacres of protesters, during the party's seven-decade grip on Mexico politics, which ended 12 years ago.

"I have memory because I know how to read," said one banner at Wednesday's march, which unified public university proletarians and the Prada-prone products of Mexico's top-shelf schools. "The truth will make us free," promised another.

The irritation hasn't been limited to the young.

A largely middle-age cinema audience in an upscale Mexico City neighborhood erupted into jeers Sunday during pre-movie ads by the fringe Green Party, which backs Peña.

"Assassin!" several people shouted at the screen, perhaps directing the accusation at Peña - though for what supposed crime is uncertain.

The two actors in the ads work on the often mind-numbing morning variety shows of Televisa, the country's dominant broadcast network. Critics particularly accuse Televisa, which for decades was closely allied to the PRI, of incessantly pumping Peña's political rise.

"We are not for or against any candidate, we just want this to be informed and fair," said Maria Jose de la Peza, 22, a business administration major at ITAM, an elite private university, as she scrawled an anti-Televisa placard.

Will it matter?

It's to be seen whether the anger means much for Peña's chances, those of his rivals or Mexican democracy, analysts say. Though they've breathed some welcome life into what was a moribund campaign, the protests remain small and Peña's advantage appears insurmountable.

Peña's two real challengers - Josefina Vazquez-Mota of the conservative ruling party and leftist Andres Manuel Lopez Obrador - remain stuck with a quarter of the vote each, according to most polls.

"No one who is informed can believe he is in the lead," Martin Iriarte, a twenty-something hair dresser who joined Wednesday's march when he came across it unexpectedly. "But everyone is discouraged by their choices. No one still knows who to vote for."

Peña and his aides seem disproportionately rattled by the outcry against him.

Canceled events

The PRI's national president blamed "intolerance" for the May 11 incident at the Roman Catholic Ibero-Americana University. Peña has since canceled several campaign appearances, or abruptly changed their locales, to avoid demonstrators.

"The guy's so far ahead there's no reason for him to step out on a limb," political analyst Federico Estevez said. But he added that if the protests grow "at some point we're looking at a much tighter race."

This week Peña vowed that his presidency would not bring a return of the PRI's autocratic style of governing, which was dubbed "the perfect dictatorship" back in the 1990s. And he condemned Tomas Yarrington, former governor of the border state of Tamaulipas, who this week was indicted on charges of narcotics-related corruption by a U.S. federal grand jury.

Much of this season's fury may be directed at Peña because he's the likely winner, Estevez said. But it also points to widespread frustration that the multiparty democracy of the past 12 years has failed to fix poverty, violence and other ills.

"The antipathy toward the PRI is much stronger than the sympathy for anyone else," Estevez said. "But people are sick of the campaign, sick of politics, sick of the parties."

dudley.althaus@chron.com