It's increasingly clear that the biggest roadblock to improving the achievement of U.S. students is violence and disorder in our schools. Education reformers say we must set high standards for student achievement and create curriculums and assessments embodying these standards -- and I agree with them. But high standards and excellent curriculums and assessments are not enough. Indeed, they will be worthless if students cannot learn because they are constantly afraid of being hit by a stray bullet or because their classes are dominated by disruptive students. This is just common sense.

A couple of weeks ago, Washington Post columnist Courtland Milloy told the story of a girl who had seen some classmates stab another student and was so terrified by the possibility of reprisals that she quit school ("An Education in Self-Help," January 29, 1995). This story has a relatively happy ending: The girl went on to earn a GED and is now attending college. But for every one who is motivated to continue her education the way this girl did, there are thousands and tens of thousands who are intimidated and distracted and are lost to school and learning.

Classroom disruption is more pervasive than school violence and just as fatal to learning. If there is one student in a class who constantly yells, curses out the teacher and picks on other students who are trying to listen or participate in class, you can be sure that most of the teacher's time will not be devoted to helping the other youngsters learn math or science or English; it will be spent figuring out how to contain this student. And it does not take many such students to ruin the learning of the great majority of youngsters in a school.

School officials seem generally to be at a loss. In Washington, D.C., and elsewhere, students who have been caught bringing guns or drugs to school or who have hurt other students may simply be transferred to another school or suspended for a little while. There seems to be a high level of tolerance for this kind of behavior where there should be none. And when it comes to chronically disruptive students, we are even more tolerant. Little happens to kids who merely keep others from learning.

Parents are painfully aware of these problems. That's why both African-American and white parents put safe and orderly schools at the top of their list of things that would improve student achievement. And that is undoubtedly why vouchers and tuition tax credits are so popular -- especially among many parents of kids in inner-city schools. These parents are saying, "If your schools are so violent and disorderly that our children can't learn -- and are not even safe -- let us put them in schools that won't tolerate kids who behave that way."

Many education experts insist that our first responsibility is to the few violent and disruptive kids. They say these kids have the "right" to an education, and we need to keep them in class and in school so we can help them overcome their problems. But what about the "rights" of the 25 or 30 kids in every class who come to school ready to work? Why are we willing to threaten their safety and learning? I'm not advocating putting violent or disruptive kids out on the streets. We need alternative programs for these youngsters, but we also need to change a system that sacrifices the overwhelming majority of children for a handful --without even doing the handful any good.

Most children come to school believing that doing right matters, but they soon learn to question that belief. Say a youngster in kindergarten does something that is way out of line -- he knocks another kid down and kicks him. The other five-year-olds are sure something terrible is going to happen to this child, and they are very glad they're not in his place. Well, what happens? Probably the teacher gets in trouble for reporting the child. So their sense of justice -- their belief that acting naughty has consequences -- begins to be eroded. The youngster who defied the teacher becomes the de facto leader of the class, and peer pressure now encourages the other children to ignore what the teacher tells them to do. At a very early age, kids are taught a bad lesson -- nothing will happen if they break the rules -- and whatever else they learn in English or math or science, this lesson remains consistent throughout school.

We have an irrational system, and it's no wonder that angry parents are calling for vouchers, tuition tax credits -- anything that would allow them to get their kids out of schools where a few violent and disruptive kids call the shots. What this means, though, is that 98 percent of students would be leaving public schools to get away from the 2 percent. Wouldn't it make a lot more sense just to move the 2 percent?