Castañeda, an internationally known intellectual with a long political history, said he's taking the road-less-traveled to the presidency because he not only wants the job he wants to lead an alternative political movement in Mexico, capitalizing on widespread voter frustration with political parties and the system in general.

It's a long shot. The Supreme Court hasn't even decided if it will consider allowing his name to be put on the ballot without a party's official nomination.

But Casteñeda brushes aside doubts, focusing his attention on selling his solutions to poverty and berating Mexico's big political parties.

Those parties as institutions are the focus of Castañeda's scathing attacks, with the most pointed comments reserved for Mexico City Mayor Andrés Manuel López Obrador, the front-runner in early presidential polling, and his leftist Party of the Democratic Revolution (PRD).

"With every day, they're more backward, more populist, more irresponsible, more devoid of proposals," Castañeda says of López Obrador and his party, speaking to The Associated Press.

While Castañeda criticizes the party establishment, he is not exactly a political outsider.

Only two years ago, Castañeda still served on President Vicente Fox's Cabinet, where he shook up relations with Cuba and reached for a major migration accord with the United States an elusive goal in the wake of the Sept. 11 attacks. His father held the foreign secretary job long before him.

Castañeda holds a teaching post at New York University and his political opinions are published in newspapers and journals across the Americas. Educated in the United States and France, he has written books on subjects as various as the revolutionary Ernesto "Che" Guevara and Mexico's relations with the United States.

Political observers say Castañeda's candidacy will appeal to the many Mexicans fed up with endless corruption scandals.

"Clearly, he's found a period where the established parties are down in the dumps. Their image problems are severe," says Federico Estévez, a political analyst at the Autonomous Technological Institute of Mexico. "He's doing pretty well." But Castañeda is seen as a single- or double-digit finisher not a potential winner. While his go-it-alone quest still needs a legal breakthrough to get him on the ballot, he also is exploring other options. Conversations are underway with the tiny Convergencia party, and Castañeda's independent campaign is organizing supporters that could represent a new political party.

When he was Fox's foreign relations secretary, Castañeda's prickly personality won him headlines and some resentment among the press. Now seeking elected office, he calls himself a straight talker.

"Yes, it's true that my style and my character and my manner of doing politics is different from the traditional Mexican way of doing things to never contradict, to never sign, to never be emphatic, to never be clear," Castañeda says. "I talk very directly. And some consider this to be arrogant and domineering. I don't see it that way." Castañeda says he wants to further lead Mexico's electoral revolution that began with Fox's surprise election in 2000, ending 71 years of one-party rule here. He says now that Mexico has real representative democracy, the country needs a "citizens' presidency" with a fresh palate of ideas to fix perennial shortcomings in classrooms, the courts and the political arena.

Castañeda's independence from party financing has prompted questions about who is backing his bid. To assuage concerns about unscrupulous connections or other irregularities, Castañeda invited the watchdog group Transparency International to review his campaign finances.

Still, Castañeda explains, his donors prefer to remain anonymous.

The reluctance by donors to go public reflects their confidence in Castañeda's chances, according to Mexico analyst Roderic Ai Camp, a professor at Claremont-McKenna College in California. Mexican businessmen who have flirted with the political opposition in the past risked being shut out of lucrative government contracts when the opposition lost.

Castañeda wants to invest in education and reform the judicial system to provide "legal security for people, goods and transactions." His plan for attacking Mexico's poverty and tepid economic growth is, in two words, oil and gas.

"I am in favor of exporting more crude as fast as possible, of extracting more gas as well and using this petroleum for spending more on schools, security, highways," Castañeda said.