He is plain. He is inoffensive. He is largely an unknown quantity. But Francisco Labastida Ochoa is the leading candidate to win the governing party's presidential nomination at a time when Mexican politics are supposed to be the most open and competitive ever.

For many Mexicans, Labastida's candidacy is business as usual in the Institutional Revolutionary Party, known as the PRI, despite pledges for greater democracy.

Although President Ernesto Zedillo has promised the first open presidential primary, they say, like every president in the past six decades, he has handpicked his successor--and now the full power of the longest-ruling party in the world is behind Labastida.

"He got there by luck, almost by accident," said Mexican historian Lorenzo Meyer, noting that the PRI continues to reward those who stay in the system and play by the rules. "He's just very mediocre. He could have been somebody else."

But while many stalwarts are following the old presidential selection script, a new one is being written by former Tabasco state governor Roberto Madrazo. He has taken the party's promise of an open primary at face value and has launched an aggressive, well-financed campaign to win the nomination in voting set for Nov. 7.

Madrazo is surging in the polls with an anti-establishment message that apparently resonates with PRI loyalists who feel betrayed by free-market economic policies that have left them broke.

The presidential primary is a revolutionary development in Mexican politics. How the fight between Labastida and Madrazo shapes up--whether Madrazo's upstart campaign is crushed by the party hierarchy, whether the primary vote is clean and fair--will give a strong indication whether the PRI's moves toward openness are genuine or cosmetic.

At a minimum, party leaders have given up some control over the selection process. But if voters feel a Labastida victory was preordained or won through fraud, they could abandon the party in droves in the general election, scheduled for July 2000. A clean vote, on the other hand, could unify and revitalize the PRI and help it win in 2000.

The former governor of the Pacific coast state of Sinaloa, Labastida, 56, majored in economics at a Mexican college and also headed the energy and agriculture ministries before becoming interior minister, a post he has since resigned. He is seen as a compromise candidate who will not split the party by alienating the ruling reformists--many educated at Ivy League colleges and known as technocrats--or the old guard, populist-style politicians known as dinosaurs.

"He's a gray figure, not a stellar personality, he hasn't accomplished much, he doesn't speak very well, he's been lackluster in every job," said Denise Dresser, a professor at the Mexican Autonomous Technological Institute. "Labastida's a compromise, a bridge candidate, someone who won't alienate the hard-liners and won't rub the technocrats the wrong way. He's the candidate of last resort."

Madrazo, 46, while not exactly a dinosaur, has nonetheless shown no reluctance to attack the legacy of the technocrats, tapping a popular vein of discontent with Mexico's economic policies. The son of a popular reformist president of the PRI, his willingness to take on authority has won him admiration, as has a media campaign asking Mexicans why so few got so much from the country's economic reforms, while so many got so little.

Two other candidates, former interior minister Manuel Bartlett and former PRI leader Humberto Roque Villanueva, round out the primary field. But none fits the definition of a technocrat, meaning that rule by the group that has run Mexico for 18 years--through the presidencies of Zedillo, Carlos Salinas de Gortari before him and, before that, Miguel de la Madrid--is coming to a close.

Technocrats will likely continue to control key institutions such as the central bank and Finance Ministry no matter who wins, analysts said. And no candidate has proposed dismantling Mexico's key reforms, such as the free-floating peso and membership in the North American Free Trade Agreement. But there is nonetheless a sense of relief that the technocrats' reign seems to be ending.

"They abused the situation and formed a small clique that pushed aside everybody else, dividing the best jobs among themselves. They offered themselves as saviors of the country, and jumped at the opportunity to change the nature of the economic system but not the political system," said historian Meyer. He called their legacy "corruption disguised as market economics."

The primary, which is looking more and more like a race between Labastida and Madrazo, is the first for the PRI, which has won every presidential election since the party was founded in 1929.

The question in the minds of everyone, from pundits to street vendors to the candidates themselves, is whether Zedillo, who has not publicly endorsed a candidate, is working privately to elect Labastida. Even if Zedillo maintains a hands-off attitude, many question whether the PRI, which is organizing and running the primary, can oversee a clean and fair vote, given its history of fixing elections.

"It could go in either direction. The PRI is used to all sorts of techniques to violate the spirit of a clean process," said Luis Rubio, director of Mexico City's Center for Development Research.

"Even if there is an election, [the rules were drawn] to give the political machine control," said Sergio Aguayo, head of Alianza Civica, an election watchdog group. Labastida "may not arouse enthusiasm among the people, but he is receiving the loyalty of the loyals. The PRI could have nominated anyone and the loyals would follow."

Researcher Garance Burke contributed to this report.

Francisco Labastida Ochoa

* 1942: Born in Los Mochis, Sinaloa state.

* 1964: Joins the Institutional Revolutionary Party (PRI).

* 1986: Appointed to first cabinet position as energy minister under President Miguel de la Madrid.

* 1986: Elected governor of Sinaloa, a farming state on the Pacific coast plagued by drug trafficking.

* 1995: Appointed agriculture minister by President Ernesto Zedillo.

* 1998: Following killings in Chiapas state, Zedillo appoints Labastida interior minister, a position that puts him in charge of anti-crime measures and resolving the Chiapas rebellion.

* May 1999: Resigns from his post to announce he will seek the PRI's nomination for the 2000 presidential race.

* Labastida Ochoa is thought to have important political allies aside from the president, including businessman Eduardo Bours, Social Development Minister Esteban Moctezuma Barragan and a large group of state governors.

SOURCE: Research by Garance Burke

CAPTION: Labastida and his wife, Maria Teresa Uriarte, greet supporters at a rally in Mexico City yesterday, when he officially registered as a candidate.