THE MUSIC program for this year's Fourth of July on the Mall is apparently being revised. The secretary of the interior, James Watt, exercising his authority as the Park Service's chief music critic and arbiter of deportment, says that he intends to change its tone. Over the years, the Fourth at the monument grounds has evolved into a kind of national picnic, with entertainment of an amiable and not very serious sort for those who choose to listen. But now Mr. Watt says he will prohibit rock music--and never mind that there hasn't been much rock there lately--on grounds that it encourages drug abuse and alcoholism.

Once again Mr. Watt is striking a posture on an issue that, in fact, time solved some years back. His declaration would have made a good deal more sense eight years ago. In the spring of 1975, as you may remember, an occasion called "Human Kindness Day" turned out very badly indeed. It was an all-day concert on the Mall of violent rock that evoked other kinds of violence in a heavy crowd. There was a shameful wave of muggings in broad daylight; hundreds of people were hurt and some were savagely beaten. The Park Service quietly changed its rules and, possibly more important, the public temper in this country changed sharply over the following years. There has been no repetition of that sorry affair.

But, hardly for the first time, Mr. Watt is playing on an impression that endures among people who live far from here and have little sense of the atmosphere on the Mall on a summer holiday these days. On the Fourth last year, a lot of families were there with children. Juvenile rebellion was not greatly in evidence. The music was not what most people would call rock. The Beach Boys, one of the bands appearing in recent years, have been at it for two decades now and are sliding serenely into middle age.

Mr. Watt proposes to bring in the Army's Blues Band, which is fine, and a singer named Wayne Newton from Las Vegas. The secretary says that his purpose is to restore family values to the occasion. Las Vegas does not represent everybody's idea of family values, or have much to do with the Declaration of Independence in any mind but Mr. Watt's. It probably doesn't make a great deal of difference which of these various musicians perform. The thing that deserves notice is Mr. Watt's determination to give an unwelcome partisan tone to a civic celebration that many people of this city cherish, and to turn a traditional unifying event into a divisive one. The secretary has a genius for generating a maximum of public irritation while achieving a miminum of real advantage for any substantial purpose, even his own.