IN A STUNNING DISPLAY of legislative insensitivity, two members of the D.C. City Council have approved a sure-fire plan to reverse any progress being made by the city's public school system. After studying budget requests for the schools in the fiscal year that will begin 12 months from now, the council's committee on education, recreation and youth affairs is proposing that 235 classroom teaching positions be eliminated from the present total, to save about $4.2 million, and that the entire adult-education program be scrapped.

Needless to say, there are ways to trim any budget request, including the school system's, without doing unconscionable damage. Moreover, it is the city council's job to review spending levels. But even with a declining enrollment in the schools, the idea of lopping 235 classroom teachers from a system that has far too many jammed classrooms right now is classic over-kill. Fortunately, the council may only set the grand total to be spent by the public schools and has no say over how this money is spent.

But the effect of the level set by the council committee would be a figure about $2.2 million less than the school board requested and $4.3 million less than the major approved. The result of this lower committee recommendation, approved by committee chairman William Spaulding and council member Willie J. Hardy, would be to force teacher cuts anyway, school officials contend.

Committee member Hilda Mason, a former school board member, is submitting a minority report seeking approval of the school board's full request. The full council should give her report serious consideration when it begins meetings today to review its committee budget recommendations.

Right now, there are classrooms in this city with 30, 35, 40 and - we're told - up to 45 students to one teacher. Those figures are alarming enough without any further fiscal damage from the council.

Certainly there will have to be some agonizing cuts in the school budgets in the coming years, with reallocation of staff, closing of buildings and other unpleasant changes. But insensitive cutbacks in classroom teachers - the front line in the education process - along with puny allowances for textbooks, summer schools and other fundamentals, are sure to undo most, if not all, of the constructive efforts by Superintendent Vincent E. Reed and a rededicated school board. We urge the city council to rescue the school system from the work of Mr. Spaulding's committee.