MONTGOMERY COUNTY'S school board has done genuine damage to a fine school system, and to the sense of equity that ties successful schools to their communities. The process of closing schools is always painful, but it doesn't have to be as disruptive and inflammatory as the series of decisions that Montgomery's board has taken over the past month.

Enrollments continue to decline in Montgomery as in most other places, and shutting some of the buildings was hardly avoidable. It was also hardly avoidable that these closings would disproportionately affect black children, since the highest proportions of them live in the southeastern corner of the county, where enrollments are generally falling most rapidly.

The board would have followed a valuable Montgomery tradition if it had tried more vigorously to reassure and work with the parents and citizens of Takoma Park and Silver Spring. But, perhaps in a reorganization that touches every part of the county, that was too much to ask. Instead, earlier this year, the board established criteria that, applied mechanically, identified the changes that needed at least to be considered. In August, the school superintendent, Edward Andrews, made a series of reasonable recommendations. But the sense of order began to break down in early November as the board approached the final decisions. The job has now been completed, in a manner of speaking, with a series of votes that justly open the board to charges of favoritism, disregard for its own policies, and excessive solicitude for the narrowest kinds of neighborhood xenophobia. Two cases in particular deserve consideration--and, we hope, reconsideration.

Rosemary Hills Elementary School lies a few blocks east of Rock Creek Park and north of the District line. Overriding the superintendent's advice, the board voted to close it. The board's majority argues that the effect will be improved racial balance in the area, since the Rosemary Hills children, nearly half of whom are black, will be dispersed among the surrounding schools. That's true, but it's more important that Rosemary Hills has been for five years the center of an imaginative and useful experiment in desegregated education. It was paired with Chevy Chase Elementary School and equipped with a Head Start program. Some of the Chevy Chase parents disliked having their very small children bused to another part of the county. Now, apparently, it's the Rosemary Hills parents whose children will be bused. That's not much of a gain for equity, and meanwhile a valuable venture in community cooperation is being destroyed.

Similarly, the board has voted to leave Montgomery Blair High School in Silver Spring with a shrunken enrollment area. Northwood High to the north is being closed, and the superintendent has proposed to send some of those students to Blair. Some of the parents objected; it is not irrelevant that more than half of Blair's students currently are black, Asian, or Hispanic. The Northwood students will, evidently, go elsewhere. The board had a chance to build a bridge over the Beltway, but refused it.

Any parent knows what drives these decisions. It's the anxiety to surround one's children with others uniformly as bright, as literate, and as well brought-up as one's own. It's the inclination to try to exclude those who don't quite measure up, without much thought of the damage that it does to them and to the community itself. That's a very human impulse but--like a good many other very human impulses--it's not acceptable as public policy.