First they invaded the radio station at American university last fall in an attempt to stop a talk show with an American Nazi.

Then they attacked American Nazi party headquarters in Arlington, injuring at least three party members in a club-swinging melee.

Last weekend, after threatening a confrontation they caused cancellation of a videotaped show of an interview with an American Nazi at George Washington University.

Who are they?

They are card-carrying, dues-paying members of the Committee Against Racism (CAR), a flinty, minuscule sect of far left hard-liners - students, government workers, unemployed, blacks, whites, Hispanies and a central core of skilled Marxist tacticians.

Their message is blunt: The American hard right must be physically destroyed.

"We must fight against these racist groups like the Klan and the Nazis," says a CAR leaflet. "Their meetings must be disrupted, their halls and literature destroyed and their members beaten."

Observance of civil rights and other constitutional rights are wasted on the Ku Klux Klan and the Nazis, says CAR member aryn Pomerantz, an emergency room clerk at GW Hospital. "We don't feel laws and courts will limit them," she said. "That's why we must take a more direct approach."

In the GWU incident last weekend, the campus program board bowed to what it called "threats promising violence" by CAR and canceled a scheduled public showing of a video taped interview with Harold Mantius, national representative of the National Socialist White Peoples Party (formerly the American Nazi Party).

CAR denies threatening violence - noting that its stated tactics of violence are directed only at the Klen, Nazis and similar organizatiosn, not at college students - but it acknowledged considering the use of loud chanting or mass sit-ins to disrupt the videotaped show telecast.

The Nazis "don't need more interviews to spread their racist lies around," said a flyer circulated by CAR on the GW campus. " . . . CAR does not believe they should have 'freedom of speech' or any freedom that helps them grow."

In the 38-minute interview taped last month. GW sophomore John R. Saler, who is Jewish, sharply questions Nazi racial policy and treatment of Jews under Hitler. Mantuis acknowledges and describes Nazi concepts of "Aryan" superiority but denies wholesale slaughter of Jews and Roman Catholics as part of German Nazi racial policy.

Saler saidhe also had planned an additional 38-minute "equal time" segment to the show in which a political science professor and representatives from black, Jewish and Hispanic campus organizations could rebut Mantius.

The Mantius interview, part of a series by Saler on controversial subjects called "GW Spectrum," also triggered protest by some rank-and-file students and representatives of Jewish campus organizations. The GW student Associations Senate voted to condemn the show during a stormy meeting at which six to 10 CAR members also noisily protested.

"The movie will not be shown unless you have a hundred cops there," shouted one CAR member, according to campus newspaper account." . . . We'll stop it."

"We urge the (student association) to stop this interview," said a CAR leaflet distributed at the meeting, "but if they don't the Committee Against Racism will!!"

Program board members responsible for the video show at first decided to go ahead with it despite the protests, then reversed themselves and they received additional indications canceled the show when they said of possible violence.

"It is against the nature of the board's members to be coerced into canceling one of its programs," said the board in a formal statement, "but because of our concern for the safety of the audence . . . we fell it is in the best interest of the students to terminate the events."

It is ironic, added the board "that certain extremist organizations who oppose these Nazi ideas are willing to use Nazi tactics if it enables them to meet their own goals."

The Washington area CAR organization, which claims 34 members, is a constituent element of the International Committee Against Racism, a closely disciplined, network of student-worker cadres that claims 1,500 members scattered among 30 major cities in the United States and Canada.

The international body has ancestral roots in the Progessive Labor party, a revolutionay Communist faction of the American left that once eas a Maoist organ but now is so militantly independent that it rejects even China as an "essentially capitalist country." according to Karyn Pomerantz, because of its trade agreements with capitalist nations and other bourgeios tendencies.

Founded in 1973 in New York City by members and sympathizers of he Progessive Labor Party, CAR has attempted to build a student-woeker alliance around a 10-point "antiracist bill of rights." Demands include a "6 hour day for 8 hours pay," restoration of all health and welfare cutbacks, busing for integration and an end to "uncritical teaching of racist theories of genetic inferiority in accredited high school or college courses,"

The Washington area chapter of CAR has small cells of activists at several employment locations including Howard University, Amtrak, Metro, Antioch Law School and U.S. Office of Education. But its group at GW University - including five to 10 employes of the university hospital - comprises the largest and most active units.

Action there has centered on unionizing low level hospital staff workers, demanding that the university shed its investments in U.S. firms doing business in South Africa and, most recently, stopping the American Nazis.

Membership in CAR is formal with members paying dues that range from $10 annually for "professional" employes to $2 for students and unemployed, according to CAR representative Sarah Harper.

Harper and other CAR activists say there is some overlap in CAR and PLP membership but contend CAR receives no formal administrative or financial assistance from PLP.

In an interview, Harper said CAR has resorted to extra-legal means to stop the Nazis, the Klan and similat organizations because "they" won't be stopped by legal means."

Pomerantz carries the argument another step: there is conscious policy by the "capitalist bosses" to allow fascism in America to grow under the guise of civil rights and First Amendment freedoms.

The reason: "There is growing unrest among students and workers in the country," she says, "and the capitalist bosses relly feel a need to control it . . . the Nazis and the KKK are the kind of initial shock "troops for this end."

The press and the courts are helping, too, she said.

"Press coverage of the Nazis and the Klan is making them appear bigger, stronger, and more viable and more attractive than they really are," she said.

As for the courts, Pomerantz cited a recent Illinois Supreme Court ruling that Nazi demonstrators have a First Amendment right to display swastikas during a planned march through Skokie, a Chicago suburb where 40,000 of the 70,000 residents are Jewish, many of them survivors of Hitler's Germany.

While CAR takes credit for invading the American University radio station last November and attacking Nazi headquarters in December, its members say they are opposed to terrorism and killing.

"We don't believe in individual acts like bombing or assassination or taking hostages," said Pomerantz. "We believe in organizing large groups for mass action, like the attack on Nazi headquarters, "

In that attack, on Dec. 10, about 40 CAR members and supporters beat at least three Nazi troopers with sticks and smashed windows in their Arlington headquarters building before county police arrived and dispersed the crowd. No arrests were made.

A month earlier, 25 to 30 CAR activists muscled their way into the WAMU radio sutdio at American University in an unsuccesful attempt to stop a talk show involving Nazi spokesman Mantius. The group splintered a doorway and smashed an on-the-air light before D.C. Police arrived and dispersed them. The program interview, conducted by AU student David Adler, went ahead as scheduled with Manius speaking by phone from Naziheadquarters in Arlington.