By JAMES C. McKINLEY Jr.

SAN MIGUEL, Mexico, Aug. 28 - After four years of hiding, the charismatic leader of the Zapatista rebel movement in southern Mexico has been holding "town hall" meetings with leftists, labor leaders, students, Indian rights advocates and other supporters in an effort to forge a national campaign to rewrite Mexico's Constitution along socialist lines.

The rebel, who calls himself Subcommander Marcos, emerged from the woods on Sunday morning surrounded by 24 armed rebels for a second day of listening to the leaders of dozens of charities devoted to social work and human rights. All the rebels wore the movement's trademark black balaclava helmets, including Marcos, who may be the only man in history to make a ski mask and pipe look sexy.

The weekend gathering looked like a cross between the Woodstock concert, a Grange Hall meeting and a convention of Che Guevara fans. At times it looked as if a public hearing in the East Village had been transported to a horse pasture in the rugged green mountains here.

More than 280 small nongovernmental organizations, artists, punk rockers, students, rappers and social workers attended - a panoply of left-leaning folks on the fringe of Mexican politics who have rallied to the Zapatista banner. Many of the charities have been formed since 1994 just to aid the Zapatistas.

The attendees included an organization representing lesbian anarchists, a collective of witches, advocates fighting the privatization of waterworks, gay-rights promoters who call themselves polysexuals and well-respected human rights monitors in Chiapas.

This was the fourth meeting of six that the rebel leaders have planned as part of what Marcos has dubbed "the other campaign," a drive to galvanize the left wing of Mexican politics before the election for president in July 2006.

In speeches at the meetings and in open letters, Marcos has labeled mainstream politicians corrupt, suggesting that it matters little for the poor and indigenous people who wins the next election. Opening the meeting on Saturday, he called for "a national leftist, anticapitalist program" and "a new constitution, which is another way of saying a new agreement for a new society."

Mr. Marcos has even tried to undermine the most popular leftist candidate, Andrés Manuel López Obrador, a former Mexico City mayor, suggesting that he and his Democratic Revolutionary Party are not true leftists and would sell out working people once in power. He has accused Mr. López Obrador, the front-runner in most polls, of being a closet authoritarian who betrayed his leftist supporters when he was mayor.

"We are going up against the whole political class," Marcos said after a contentious meeting with left-wing political organizations on Aug. 6, "for all they have done to us." He declined requests for interviews.

Precisely what Marcos hopes to accomplish with the meetings and with a planned national tour by a group of Zapatista representatives remains murky. He has not defined how he would change the Constitution.

He has denied that he wants to enter politics himself or to convert the 11-year-old rebellion into a political party, even though the administration of President Vicente Fox has said it will make that transition possible if the rebels disarm.

The Zapatistas have not mounted a major military offensive since they were pushed back into the mountains by the military in 1995. After Congress failed to pass an Indian rights bill the rebels had advocated, they set up "autonomous municipalities" that reject government aid.

The rebels who appeared with Marcos did not look like a formidable fighting force. Several were teen-agers. One woman carried a crippled chicken that Marcos had adopted as a mascot and dubbed Penguin, because he waddles like one. Of the 24 armed rebels, only a handful carried automatic rifles.

Some cynical political analysts have said Marcos wants to distance his movement and other hard-line leftists from Mr. López Obrador to help the former mayor with moderate voters.

Others have said Marcos's true aim is to restore to power the Institutional Revolutionary Party, the authoritarian machine that ruled Mexico for seven decades, to revive his fading rebellion by reviving its nemesis. (On Saturday, Marcos called the idea "a story to fool idiots.")

Still others say Marcos's call for a broad movement reflects a widespread disappointment with left-leaning politicians throughout Latin America, who have become enmeshed in the sort of corruption scandals they once criticized.

"What they are saying represents a trend in Latin America, which is that people have lost faith in political parties," said Peter M. Rosset, an expert in agricultural policy who attended the meeting on Sunday. "The basic feeling is that the political class is all the same."

That sentiment was expressed over and over here in San Miguel, a former 15,000-acre ranch that the Zapatistas seized in 1994 and divided among former Indian ranch hands.

"This movement, for me, its historic," said Arturo Guzmán González, a 29-year-old singer who did a version a cappella of his protest song, "Manifestarse." "It has a moral base, this movement. They seek the words of everyone."

Words there were aplenty. Rebellion was celebrated. Violence against homosexuals was decried. The mainstream media was derided as untrustworthy. The evils of capitalism were roundly criticized, while the virtues of socialism, communal farming, organic foods, same-sex marriage and human rights were expounded at length.

Some participants grew tired of waiting to speak and left early. A few questioned how they were to change the Constitution without forming a political party. Several despaired at all the high-sounding speeches.

"We need more concrete proposals," said Claudia Ledesma, of the Society of Popular Organized Alternatives, who had gently suggested the formation of committees to study issues. "If not, we run the risk of losing ourselves in the words, or in an illusion."