Available immediately: Bodyguards for presidential candidates. Team comes complete with sentries for the entire family, armored vehicles, guns, bulletproof vests and communications gear. Free of charge, compliments of the government.

Meet the bodyguards nobody wants.

With the official kickoff last week of what promises to be Mexico's most protracted and openly contested presidential campaign in seven decades, the government took the unprecedented step of offering all major candidates the protection of federal police agents a full year before the election.

But in a nation where nobody seems certain whom to trust--and where the unresolved assassination of the front-runner in the last presidential campaign remains fodder for inexhaustible conspiracy theories--there are no takers.

"I'm not going to accept the bodyguards from the attorney general's office," said Francisco Labastida Ochoa, a leading candidate for the presidential nomination of the ruling Institutional Revolutionary Party, known as the PRI, who recently left President Ernesto Zedillo's cabinet to launch his campaign. "I prefer those in whom I have total confidence."

This is the latest affront to the Mexican government's credibility in a presidential contest that is rewriting the rules of electioneering and governance in a country accustomed to seeing its president handpick his successor and its campaigns manipulated by the longest continuously ruling political party in the world. The rejection of the use of federal police by men who hope to lead the country also underscores the deep distrust of Mexico's law enforcement agencies, which officials say are infiltrated by criminals and beholden to competing cliques within the government.

Others argue that some candidates have turned down the bodyguards in a show of machismo.

"It's not a high priority or essential for me," declared Manuel Bartlett, a PRI candidate representing the traditional wing of the party.

Both main opposition candidates--Cuauhtemoc Cardenas of the leftist Democratic Revolutionary Party (PRD) and Vicente Fox of the conservative National Action Party (PAN)--have turned down the bodyguard offers, as have all four PRI contenders.

"If a candidate--for reasons that he considers prudent--decides not to accept [the government bodyguards], that's within his rights," Jorge Alcocer Villanueva, the undersecretary for political development in the Interior Ministry, told reporters last Monday.

The government seeks to thwart a repeat of the 1994 tragedy when the PRI's candidate was gunned down while campaigning in a poor Tijuana neighborhood five months before the election.

Perhaps just as shocking as the murder itself was the proliferation of motives offered, including allegations that Luis Donaldo Colosio, a young reform-minded candidate, was ordered killed as a result of internal party conflicts. Police arrested a gunman, but never identified a mastermind behind the crime, compounding the web of conspiracy theories that has turned the Colosio killing into Mexico's version of the murder of President John F. Kennedy.

"Protection in Mexico has always been a problem," said one Mexican political observer. "The candidates don't know whom the guards work for. The people being protected are obviously under surveillance. . . . I, as a candidate, would rather not have these guys following me around and feeding to someone the details of whom I met with, how many miles I traveled and who my mistress is."