The trouble all started when Secretary Watt started reading the newspaper of the capital and learned they had been playing all this rock music on the Mall at Fourth of July celebrations.

It took only two or three years for the secretary to become aware of this reality, which says a good deal for the incredible power of the press, since without it he would certainly have gone to his grave unaware (from his perch up on top of a building, where he entertained friends at the Mall festivities) of what was going on.

A lot of young people, it became clear to the secretary after a few years, had been gathering to hear such rock groups as the Beach Boys. And naturally if you get a lot of youths lunging about to BOMP, BOMP, BOMP, you're going to have pot-smoking here and there and "alcoholism." That's Watt's word for beer.

But now, thanks to the grand enlightenment in the Reagan Cabinet, the state perceives it has been encouraging the wrong kind of American down on the Mall, and we are fixing to attract the right kind. The military, who are patriotic, instead of the rock groups (who are unpatriotic?). They'll play this year and attract a better sort. Families.

Yesterday, of course, Secretary Watt backed down somewhat, after President Reagan said Watt had shot himself in the foot and after Nancy Reagan and a batch of high White House officials all indicated they thought the rock of the Beach Boys was positively like apple blossoms and pie. We will wind up, no doubt, with a different band every hundred feet on the Mall, as the lesson of plurality is increasingly learned (or at least acceded to) by Secretary Watt.

I do not want to sound superior to Secretary Watt in some petty way, however, and should say that for my part I don't like the Beach Boys or Wayne Newton or the Salted Slugs or the Coated Cashews or any of the others enough to do anything except arrange not to be within hearing distance of them. Why not Gabrielli? Why not Bach? I think we should be told. But then it has been a long time since I counted on any American government to provide entertainment beyond the White House, the Cabinet, the Senate and the Post Office Annual Report.

Where we differ, Watt and I, is that unlike him I do not believe that all the folk attracted to the Mall on the Glorious Fourth are necessarily the wrong kind of people, even though it turns out Edwin Meese and all those people are among the throng.

Let a thousand flowers bloom. Let those who like getting squashed, who like getting heat strokes, who like getting screeched at by singers who cannot project a voice 20 feet without electronic boosters, all take their joy on the Mall, it's no skin off my nose and why shouldn't they all have fun.

That's the crux of it: the fairly hair-raising fact that some people prefer the Cashmere Toads to Fritz Wunderlich (dead, alas, as so much glory is) does not mean that the toad crowd is not patriotic, loyal, courteous, reverent, kind. They are missing the big triumphs of music, but then they're mostly young and Confucius always said you should give a guy about 70 years to get himself together. Charity is the word for all. Something that noodle at Interior might reflect on.

There's no point beating a dead horse, or commenting sensibly on a jobbernowl, and in his defense I should say this about the secretary: there is no asinine statement he can make that would surprise a single soul.

It comes of being born dumb and standing fast forever. There will always be employers of last resort, such as an American president, to hire you.

In brainy places, on the other hand, such as the Woodrow Wilson Center at the Smithsonian, they keep having these nagging visions that possibly Americans have gotten sufficiently stupid, or sufficiently lazy, that we can no longer do the work required to keep the nation rich or strong or cheerful.

We do have one thing going for us. There is nothing we can do, fortunately, to keep the average new-born human from having normal intelligence. Any stupidity is therefore acquired from the environment.

You may read nowadays that 20 percent of Americans are functionally illiterate, which merely means they can't read, but the crucial statistic is the number of Americans as dumb as Secretary Watt, whom literacy has not helped at all.

Education, after all, does not equate to formal education, but consists of what we hear, and what we see is workable. An important American lesson is that Watt can become a Cabinet officer. There is no doubt that much American thought springs from the observation of such a truth.

In other words, teachers should not be blamed for education that Americans have acquired elsewhere than the classroom. Teachers in schools are always being fussed at unjustly, merely because so many of them were denied an education themselves.

It would be wrong, as I say, to blame teachers, many of whom must have given up exciting jobs as cocktail waitresses to help the young.

It is quite wonderful, besides, how much cheer a monumentally stupid teacher can bring to the general public. Some of the most incredible teachers are good for some of the best guffaws over Washington breakfast tables. We had a pretty example this week in the daily paper, featuring a teacher who sold a story to a magazine. The story incorporated, and depended largely on, words written by a pupil. The kid writes something, the teacher sells it, pretending the kid didn't write it at all. One is sometimes struck by the exquisite delicacy of the pedagogue.

But the teacher, who was not born yesterday, cautiously consulted a lawyer, she said, before incorporating the pupil's work in the story. Somewhere (and this bears out my claim that all humans have brains) in some dark cavern above the neck shone a tiny glimmer of memory or of doubt, that there may be times you cannot legally sell the written work of other people as your own. The lawyer told her, she said, that since the pupil's work had been published, it was freely available for the teacher to lift.

It seems unlikely that any kid applying for entrance to law school, let alone finishing it, could give such advice. But then it is equally unlikely that any teacher would rely on such idiocy even if it were offered.

It is not, however, all that unlikely that such a teacher is teaching.

I think teachers are affected by the Board of Education in some deplorable way, and may actually model their brains on board members who specialize in gibberish. As an example of that, here is a paragraph from a letter written by a board member for publication in this newspaper this week:

"The evaluation process agreed to by the board . . . was intended as an internal gauge by which to plan and improve upon that which has already been accomplished and to shore up any areas of concern that were surely to emerge with 12 diverse individuals . . . merging their ideas of educational excellence and achievement."

Their ideas of excellence my eye. What this country needs is a good fourth grade teacher and a sharp penalty for any secretaries, teachers or board members who skipped a few years and never made it up.