Slim’s aides have fought any debate about how Telcel imposes excessive charges on competitors to use its network or about its high consumer rates.

“Any discussion of high prices leads inevitably to the discussion of its extremely high profits,” said Victor Pavon Villamayor, the Oxford-trained director of new regulation at the Federal Telecommunications Commission. A report released in late January said overcharges to phone and Internet clients by Slims’ companies cost Mexico $129 billion from 2005 to 2009, losses equal to nearly 2 percent of the nation’s annual economic activity.

That study – commissioned by the Mexican government and conducted by the Paris-based Organization for Economic Cooperation and Development, a forum of 34 nations – was rife with “manipulation of facts and flawed economic analysis,” charged Daniel Hajj, the chief executive of America Movil, a Slim-controlled cellular company that’s Latin America's largest and is the parent of Telcel.

Still, under the threat of an unprecedented $1 billion fine last year, Telcel has scaled back its fees. Last month, regulators revoked the fine, saying Telcel had agreed to reduce charges to competitors for calls that ended on the Telcel network.

Slim’s image is benign, however, compared with that of the man known as “El Tigrillo,” or “Little Tiger,” Emilio Azcarraga Jean, the 44-year-old chief of Televisa, the most successful television network in the Spanish-speaking world. In recent weeks, thousands of university students have poured into the streets in anger at what they assert is Televisa manipulation to help its favored candidate for the presidential election.

That charge has historical roots. Televisa was long associated with the Institutional Revolutionary Party, known as the PRI in its Spanish initials, which ruled Mexico for 71 years until 2000, and now appears poised to retake the presidency July 1. Azcarraga’s father once famously said: “I am a foot soldier of the PRI.”

Televisa’s reputation for bare-knuckles defense of its vast business empire – which includes publishing, cable TV, film production, soccer teams and slot machine parlors, including a large interest in the U.S. Spanish-language network Univision – burdens Azcarraga.

“He has a huge image problem,” said Garcia, the financial journalist. “Azcarraga comes off as the ‘evil businessman.’ ”

It’s not just Televisa, which captures 68 percent of television-viewing eyeballs. It’s also the separate TV Azteca, which holds a 29 percent share, leaving only 3 percent for a smattering of remaining channels.

“Politicians are truly afraid of the television networks,” said Carpinteyro, the former federal communications official. “They don’t want to have the television networks as enemies because if they do, they would disappear from the TV screens.”

Like Soviet propaganda masters of yore, Televisa has taken reprisals against politicians opposed to its interests. The most notorious case occurred in July 2008, when a Televisa newscast twice pixelated the image of then-Senate President Santiago Creel during a debate. It later claimed a production mishap.

Creel, who’d criticized a regulatory law favoring Televisa, demanded that the network be punished. Instead, in a demonstration of Televisa’s clout, Creel’s National Action Party colleagues ousted him from a leadership post, forcing his removal as Senate president.