In a recent editorial ["Culture and Anarchy," May 8], The Washington Post took the National Endowment for the Arts to task for having "given up its role as a national leader in cultural affairs."

The editorial took its cue from an inaccurate and misguided report by two investigators for the House Appropriations Committee. In classic "have-you-stopped-beating-your-wife?" fashion, the investigative report chastized the Endowment for its supposed failure to live up to its congressional mandate "to develop and promote a national policy for the arts."

The first Problem with the report's allegation is that the investigators fastened on the wrong mandate. In its authorizing legislation, the Endowment is given the responsibility "to develop and promote a broadly conceived national policy of support for the humanities and the arts.

Though some have concluded that the United States should follow the Europeans in developing a national arts policy, that was not the intent of Congress in establishing the Endowment in 1965, nor has it ever been since. I believe I can speak with no small authority on the matter since it was I who helped draft the authorizing legislation, who served as the agency's first deputy chairman, as congressional liaison for the Endowment and as a staff member of the Senate authorizing sub-committee. The investigative report is plain wrong about this allegation as it is about so much else.

One of the greatest fears that arose about establishing the two Endowments was precisely this: that it would lead to a national governmental policy for the arts and humanities. So great was congressional and citizen apprehension on this point that the Endowments were specifically enjoined by law from exercising "any direction, supervision, or control over the policy determination, personnel, or curriculum or the administration or operation of any school or other non-federal agency, institution, organization or association."

It was clear that both Endowments were to "complement," "assist," "support"-all words taken from the legislation-and not direct. Cultural czarism was deemed foreign to the American experience. The private sector in the United States, unlike other countries, had always provided by far the major portion of support for the arts, and Congress wished to keep it that way.

The second problem with "abrogation of leadership" charge is that even if the investigative report had settled on the Endowment's true mandate, it would have been wrong to conclude that the Endowment had somehow failed to heed it.

One of my first steps as new chairman of the Endowment was to launch the deliberate process that resulted last year in a statement of the Endowment's goals and basic policies and this year in a 150-page long-range plan built upon those policies. The policy statement was cited approvingly by the investigators and praised by subcommittee chairman Sidney Yates during the Endowment's appropriations hearings. The essential importance of the plan has been approved by the National Council on the Arts, the Endowment's advisory body of distinguished private citizens.

I cannot emphasize too much, however, that the policies outlined in both documents are policies for support of the arts, not policies for the arts. We have not been derelict in complying with our mandate, but we have been firm in our refusal to go beyong it.

The Post's editorial repeated the charge levied against both Endowments that their panels and committees represented elitist, overlapping "closed circles" of friends giving grants to friends.

Well, it was not too long ago, it seems to me, that the agency was being buffeted in the press for being too populist, for letting down the drawbridge and opening up the Endowment to hordes of non- or pseudo-artists, the Barbarians, Philistines and Populace identified by Matthew Arnold in his essay "Culture and Anarchy," the curious title of your editorial.

I suggest that neither characterization if true. The Endowment, though a small agency, is very complex; on that is subjected to such gross stereotyping only through a serious lack of knowledge or of good will. The facts are that 56 percent of Endowment panelists, which review the 18,000 applications we now receive annually, have never previously served on the Endowment panel; only 5 percent are returning to service after an absence of four years. The rest are completing their terms and awaiting rotation off the panels this year or next. Where if the alleged closed circle?

During the past year the Endowment has greatly increased the responsible role its private citizen advisers play in policy and grant review; instituted a policy of rotation for senior program directors so that the fresh air of new ideas can be ventilated; strengthened its response to minority concerns so that more than 11 percent of available program funds now support these activities; and taken new steps to develop a true partnership with state arts agencies, whose total annual state appropriations for the arts now exceed $80 million.

All these efforts are aimed at improving the quality of the great diversity of the arts and at making that quality available increasingly to our citizens.

National priorities in the arts have been presented to the Congress. A plan has been prepared.

Chairman Yates of the House sub-committee which oversees the work of the Endowment has expressed his disappointment in the apparent lack of an objective report and his sense of a lack of constructie approach.

it would now seem time to assess correctly the contributions the Endowment makes to the arts in our nation, and then to move forward constructively toward the future.