According to an old Benjamin Franklin poem, for the want of a nail a war was lost. In Franklin's Philadelphia this week, for the want of reason, a whole city block was lost, at least 11 people died, sixty homes were destroyed and 300 people were left homeless with nothing but the clothes on their backs.

Following repeated complaints from residents of a black working-class neighborhood about a house occupied by members of a radical, back-to-nature group called MOVE, police Monday attempted to evict the estimated 20 members occupying the row house. While neighbors complained that the group had guns and harangued them at all hours with obscene tirades over loudspeakers, the police had older recollections of MOVE. In l978, a police officer was killed as police attempted to enforce a court order and got into a shootout with MOVE members.

Responding to this new challenge by the self-styled cult, Mayor Wilson Goode and the police department decided on a plan to evict them that, according to Goode, "called primarily for the use of water and tear gas to force them to surrender." According to police, cult members refused to come out of the house when ordered to leave. A few minutes later a deafening barrage of gunfire began, continuing for more than an hour. Although an estimated 7,000 to l0,000 rounds of ammunition were fired into the two-story house, the occupants refused to capitulate.

"What we have out there is war," Goode said at this point. When asked by the media what he would do to remove the group from the house, he said, "We intend to take control of the house by any means necessary."

But by no stretch of the imagination did anyone dream that Goode and the Philadelphia authorities would think of using a percussion bomb. Yet that is precisely what they did. "The plan was a good one," the mayor said even after the area lay in ruins. "It could have worked."

But the plan didn't work. A fire was set off by the bomb. A raging inferno was created, devouring everything in its path, including the homes of innocent citizens, even melting cars a block away.

The move to drop a bomb in a residential area represents a staggeringly serious error in judgment, but the miscalculations did not stop there. After the fire started, as walls crumbled and Osage Avenue took on the appearance of a bombed-out city, like Dresden at the end of World War II, Philadelphia police waited for 90 minutes before even calling fire officials. The mayor later explained: "Three members had been spotted in the alley and had engaged the police in fire. We did not want risk the lives of firefighters."

Hearing that "explanation," I concluded that I just don't understand human beings anymore. The job of the police is to protect the public by containing the use of violence, not expanding it. The decision to bomb Osage Avenue was an overreaction of extreme proportions.

Ironically, the sad and frightening thing is that the men who used this juggernaut of force, this overkill, if you will, are black. Leo A. Brooks, the former Army general who is the city's managing director, said of his decision to drop a bomb, "We believe we did what we thought was appropriate for the occasion."

Mayor Goode, of course, has a reputation of being one of the country's most stable, professional and even-handed mayors. But as a former Army military policeman, he is no neophyte in the art of weaponry. Shouldn't these two ex-military men have at least contemplated in advance that this dangerous plan had a 90 percent probability of going tragically awry?

There is an intimation here of black people devaluing black life, and some blacks have pondered whether Goode and Brooks would have acted in the same way if that house had been occupied by a group of equally loony and offensive white radicals in a neighborhood in Germantown or Walnut Hills.

One can only hope that the citizens of Philadelphia will ask hard questions of the mayor and that blacks particularly will lead the inquisition. I also hope that other mayors, white and black, will learn from this tragedy that it is suicidal to wantonly use unnecessary force.

But most of all, I hope Wilson Goode learns from the experience. In this fast-paced and difficult world, everyone is allowed to make one or two major mistakes in a lifetime. In one day, Wilson Goode has just about used up his allotment.