VIOLENT SUBWAY CRIME in New York City unfortunately provided an excuse in many people's minds for the Guardian Angels, a para-military youth safety organization. Citizens there and in many other big cities are justifiably frightened to travel at night because the police can no longer provide anything approximating a safe ride. But in our alarm over urban disorder, we should not herald the Angels as saviors without taking a closer look at the nature of the group.

Led by Nurtis Sliwa, a man who many say is as interested in press conferences as he is in justice, the Angels claim they deter crime merely by their presence. Though it would be hard to prove this assertion, it seems reasonable that subway passengers would at least feel more secure, if not actually be more secure, under the Angels' watchful eyes. Yet as they spread out to Boston and elsewhere, Sliwa's troops have implicitly broadened their self-appointed mandate. Here, they have promised to patrol streets in dangerous neighborhoods, particularly in areas known for severe racial tension. Encouraged by excessive media and a glut of enlistees, the Angels seem to be drifting toward a confrontational stance they could never have held when they were but a few squads of diehards operating out of Sliwa's New York City apartment.

More troubling is the realization that under questioning, even the most sophisticated Angel will recite stories of gang wars won, bullets whizzing overhead and knife wounds to the abdomen. We should certainly wonder whether Sliwa's expansion program will attract public-spirited kids concerned about purse snatchers or toughs who are only too happy to find a sanctioned duty as inner-city commandoes.

Ideologically, we oppose the whole idea of uniformed vigilantes mobilizing wherever they deem their presence is needed. Romantic visions of wild, wild West ranchers hunting down evil bandits should not overshadow other examples in our history of people taking the law into their own hands. The Ku Klux Klan, after all, lynched for the sake of Southern order and womanhood.

The Guardian Angels have yet to prove themselves a long-term threat to proper law enforcement. Their surfacing has focused attention on our failure to protect city residents. We must react to that failure by spending more money to pay more policemen, even if that means raising taxes and scrimping elsewhere. But we should not endorse the growth of an unregulated, privately run group of trained strong-arms. The Angels' leadership now seems a bit mysterious--some day we could conceivably find it dangerous. Their rhetoric is bold; it could become threatening. Before t-shirts become brown shirts and someone starts talking about making the trains run on time, perhaps we should reconsider the welcome much of Boston extended to these youthful vigilantes.