Aztlan is a country with no borders and no government, but it has a militant student movement with big plans.

Some of the activists dream of the day when they can 'liberate' a large portion of the southwestern United States, which they consider to have been stolen by gringos, and raise their own flag over it.

'The ultimate ideology of MEChA [the Movimiento Estudiantil Chicano de Aztlan] is the liberation of Aztlan,' the entire southwestern portion of the United States, says Miguel Perez, the group's publicity chairman at California State University at Northridge.

Activists for MEChA, which subsists mostly on public funds, consider the region to be occupied by a foreign colonial power.

Though this sounds like a child's fantasy to Americans who live in this region, MEChA is a growing and increasingly militant presence on certain American campuses.

'The purpose of MEChA is the empowerment of our people,' says Jacqueline Carrasco of University of California at Los Angeles.

An advocacy group to aid Chicanos in education and civil rights issues, MEChA promotes bilingual education and opposes the North American Free Trade Agreement, and some of its members endorse radical aims.

'They are irredentists - These are people who want to go back to pre-1848 borders and who believe that their land was stolen,' says Linda Chavez, a former U.S. Civil Rights Commission member and author of 'Out of the Barrio.'

Others don't disagree. 'The concept of Aztlan is a varied one related to the legendary beginnings of the Aztecs,' says Rudolfo Acuna, an outspoken Chicano activist and professor at Cal State Northridge.

Mr. Acuna said he does not know when there will be an actual country called Aztlan, but he clearly holds out the possibility. Like many in MEChA, Mr. Acuna feels 'an affinity with Mexico' because 'this country does not give you very much to feel part of.'

For syndicated columnist Raoul Contreras of San Diego, 'there never was a country called Aztlan and never will be.'

Mr. Contreras, who prefers the designation Mexican-American, argues that the Aztecs never lived in what is now the Southwest and, since they originally came from Asia, 'their mystical homeland is somewhere in Siberia.'

Many historians also note that the Aztec empire mostly encompassed the area that is now southern Mexico and did not extend into the region claimed by MEChA as Aztlan.

Mr. Contreras argues that MEChA promotes 'class warfare' and is composed of 'children of the peasant class who don't see themselves ever being middle class.' He's 'glad people are getting together' and says MEChA makes 'substantial points, but they make themselves look foolish when they rehash something that is now almost 150 years old.'

'I never hear them complaining about all of Central America breaking off from Mexico. It all depends who is doing the stealing.'

The activist Mr. Acuna, who describes himself as a socialist, says MEChA emerged in 1969, when the United Mexican American Students and Mexican American Student Association met in Santa Barbara and decided to 'put all groups in MEChA.'

MEChA members decline to estimate their overall membership. But Miguel Carillo, a high school teacher in Chula Vista, says MEChA chapters are in more than 90 percent of the high schools in San Diego and Los Angeles and almost every college and junior college in the area.

Moreover, MEChA groups now are on college campuses in some 10 states, including Washington, Colorado, Utah and Illinois. MEChA depends largely on public funds.

'Most chapters get their budget from the schools, sometimes from the associates students,' says UCLA's Miss Carrasco. High school and junior high school chapters have to raise their own money.

The money MEChA receives from schools ranges from $100 at some campuses to nearly $8,000 annually at large schools such as Cal State Northridge, she said.

Student publications featuring MEChA material include El Popo, Aztlan News, Chispas and UCLA's Gente de Aztlan, whose 'Universal Council of Elders' includes 'Mother Earth,' Marxist revolutionary Che Guevara, Augusto Cesar Sandino, Crazy Horse, Simon Bolivar and Salvadoran Stalinist Farabundo Marti.

Voz Fronteriza, published at the University of California at San Diego, bills itself as 'the most wanted paper in Aztlan,' seeking subscribers with this offer 'The pigs read our paper. Why shouldn't you?' A recent cover asked, 'When will we come to the conclusion that revolution is the only solution?'

Voz staffers, who describe themselves as 'guerrilleros de la pluma' (warriors of the pen), also produce a cable television program.

Asked what type of government he would prefer for Aztlan, Mr. Perez, MEChA's publicity chairman, replies without hesitation that 'communism would be closest.'

'Like Cuba, but a little broader than that,' he says, noting that this is his personal view, though many others in MEChA share it.

Once Aztlan is established in the American Southwest, non-Chicanos 'would have to be expelled' and anti-government demonstrations would have to be quashed 'because you have to keep the power,' Mr. Perez says.

Mr. Carillo, the high school teacher, says that much material in MEChA publications can be described as extremist but adds that such views do not play a dominant role in the group, especially at the high school level.

MEChA is 'inclusive,' Mr. Carillo says, and its purpose is to 'explain our culture.'

However, a case featured in Campus Culture Wars, a documentary now being broadcast on public television, shows that MEChA hard-liners can easily push out moderates.

Rudy Fuentes, the first Chicano to become student body president at Stanford University, helped revitalize the MEChA chapter on campus. Yet he soon found himself confronted by a faction that wanted to ally with more radical groups and rejected his practice of working within the system.

The hard-liners surrounded Mr. Fuentes, poking him and calling him a 'vendido,' or sellout. 'Their intent was to instill fear,' he says. ;