From the Boston Tea Party to the Vietnam anti-war movement, Americans have a long tradition of breaking the law to further a political goal. Now these same tactics of harassment and even violence are increasingly seen in the medical arena. Abortion. Animal rights. AIDS. All are controversial issues that trigger strong passions of rage and righteousness along with fear and prejudice.

Just last week, a fireworks expert was sentenced to prison for his role in bombing abortion clinics in New York City.

In late August an underground animal rights group called the Band of Mercy broke into the U.S. Department of Agriculture's 7,000-acre research laboratory in Beltsville, Md., and stole 28 cats and other experimental animals.

In Arcadia, Fla., a suspicious fire last month gutted the house of Clifford and Louise Ray, whose three sons are hemophiliacs and tested positive for carrying the AIDS virus. A federal district judge had ordered the schools to admit the boys to regular classes over protests of the community. After the house burned down, the Rays said they had to find safety by moving away.

"We have a long history of using violence to redress somebody's definition of wrong," says Dr. Joe P. Tupin, professor of psychiatry at the University of California at Davis. "We have validated and romanticized violence. The ends and means get to be a little confused."

Most mainstream advocacy groups such as the National Right to Life Committee oppose the use of violence. Yet, as the phenomenon of protest movements shifts from strictly political questions to health issues, there has been a rise in a kind of medical vigilantism.

Research on the natural evolution of liberation movements, be they political or medical, shows that once a movement gets started it tends to attract people who are less and less able to distinguish between appropriate and inappropriate activity. "In the extreme," said Dr. Frank Ochberg, adjunct professor of criminal justice at Michigan State University in East Lansing, "zealotry clouds the ability to think logically."

Abortion, especially, has been a lightning rod issue since the 1973 Supreme Court decision Roe v. Wade made it legal for women to have an abortion. With the pope's visit this week and the nomination of Robert H. Bork to the U.S. Supreme Court, groups supporting abortion rights are bracing themselves for a new round of militancy on the part of pro-life anti-abortion advocates.

"I'm worried about the rest of 1987," said Barbara Radford, executive director of the National Abortion Federation, which represents about 300 clinics where more than half of all abortions in this country are performed. "We're likely to see an increase in violent activity and harassment. As soon as the rhetoric starts, we see an increase in activity."

Since 1982, the Bureau of Alcohol, Tobacco and Firearms has investigated 62 incidents of bombing or arson at abortion clinics. A fire at the Hillcrest Clinic in Norfolk, Va.: $250,000 damage. A fire at a doctor's office in Houston, Tex.: $400,000 damage. Bombing of the Metro Medical and Women's Center in Wheaton, Md.: $300,000 damage. A fire at the Planned Parenthood Clinic in Kalamazoo, Mich.: $750,000 damage.

Now militant action is getting more personal. Physicians and nurses have received death threats and had their homes picketed. Women who come to abortion centers have been traced by their license plates and harassed by pro-life advocates.

An extreme case involves Bethesda gynecologist Dr. Alan J. Ross. Antiabortion activists have picketed Ross' home in Potomac, his office in Bethesda and an abortion clinic where he works in Gaithersburg. Last month a county circuit court judge signed an order not against the pro-life picketers but against Ross, forbidding him from performing abortions at his Bethesda office because the demonstrators were disturbing other businesses in the office complex.

A survey by the New York-based Alan Guttmacher Institute found that in 1985 nearly half of the clinics reported bomb threats and incidents where patients had been physically blocked by picketers from entering the clinic. Almost 30 percent said that demonstrators had entered their clinics illegally; 22 percent experienced jamming of telephone lines, 28 percent reported vandalism and almost 20 percent said members of the staff had received death threats.

Of course, pro-life supporters bring a high moral tone to their militancy. In hearings before U.S. House of Representatives subcommittee on civil and constitutional rights, Joseph M. Scheidler, executive director of the Pro-life Action League, said of violence against abortion clinics: "I wouldn't condone it but I wouldn't condemn it . . . Knowing what takes place inside the abortion chambers, we understand the moral outrage at the waste of human life that prompts this response . . . when there is a higher law, a lower law has to submit to that."Animal rights activists also have their share of militants.

Since 1982, some 32 incidents including break-ins, animal thefts, damage to equipment and bomb threats have occurred at research laboratories and animal facilities.

"Yes, it's escalating. We've never seen the degree of violence in this country that we're seeing right now," said Frankie Trull, president of the Foundation for Biomedical Research, formed in 1981 to foster public understanding of the use of animals in medical research.

That same year, the People for the Ethical Treatment of Animals (PETA) was founded in the United States to promote animal rights. Militant groups that have claimed responsibility for raids include the Animal Liberation Front, Band of Mercy, True Friends, and Urban Gorillas.

Last April, members of the Animal Liberation Front broke into the University of California at Davis and set fire to an animal diagnostic laboratory under contruction, causing $3.5 million in damage, according to estimates by the National Institutes of Health. Three years earlier, fake bombs were planted at the doorstep of a UC-Davis professor who headed the California Primate Research Center.

In April, 1985, ALF members broke into the University of California at Riverside and stole a menagerie of cats, rabbits, pigeons, oppossums, rats, mice, gerbils and an infant monkey.

In December, 1986, the True Friends claimed responsibility for stealing four baby chimpanzees to be used in AIDS research from Sema Inc., a biomedical facility in Rockville.

Once again, medical militancy is justified by its supporters on moral grounds.

"We don't engage in illegal activities such as break-ins, but we don't condemn them," said PETA's Patrice Green. "The most important goal is to put an end to animal suffering where ever it occurs. A strong analogy for us is the abolitionist movement -- in this day and age, it is the animals that are the slaves."

Besides, militant action sometimes works. In April, 1984, ALF members broke into the University of Pennsylvania Experimental Head Injury Clinic in Philadelphia and stole research videotapes and destroyed laboratory equipment. The tapes were given over to PETA and edited into a 29-minute film that showed alleged mistreatment of animals. Nevertheless, NIH continued to fund the controversial laboratory.

In July, 1985, 100 animal rights supporters staged a sit-in on the eighth floor of Building 31 on the NIH campus in Bethesda and didn't leave until NIH agreed to close the laboratory. "It was extremely exciting," said Green. "More than likely, none of that would have happened if the tape hadn't been brought out. It was the lab that was breaking the law."AIDS now has exploded onto the medical scene as a complicated political issue. Like abortion and animal rights, acquired immune deficiency syndrome can provoke moral outrage. It also unleashes deep fears that the spread of the virus is out of control -- even though all the evidence so far indicates that the disease cannot be transmitted by casual contact.

The hounding of the Ray family in Florida stands out as one of the more egregious examples of community fear and prejudice. But the boycott of the Ray boys in school is not the first time communities have tried to block children infected with the AIDS virus from attending school, and as the disease spreads disporportionately among homosexuals and intravenous drug abusers, probably not the last instance of discrimination.

It's probably no accident that most of the targets to date of AIDS-related violence have been homosexuals. In cities such as New York and San Francisco where the level of anti-gay violence has increased in recent years, AIDS is blamed as the main factor.

"It gives those people who already hate gay people an excuse for harming them," said Kevin Berrill, violence project director of the National Gay and Lesbian Task Force, based in Washington, D.C. "AIDS has helped to validate that prejudice."

San Francisco's Community United Against Violence (CUAV) has found that serious incidents against gays requiring surgery or hospitalization jumped from 10 attacks in 1986 to 33 so far this year. In two cases, people lost their sight in one eye when chains were raked across their faces. Another victim spent six weeks in a body cast after he was beaten up.

"I think the identification of AIDS with the gay community plus a political climate that is decidedly more repressive against minorities has increased the level of violence," said Carmen Vesquez, a community organizer with the San Francisco group. "People feel more emboldened {to commit violence}."

In the face of medical vigilantism, there is a need for strong political leadership to help prevent further escalation of violence. "The thing that concerns me," said pyschiatrist Tupin, "is that I don't hear the voices of people elected to office saying: 'Hey, that's wrong.' "