Mary McGrory's column yesterday incorrectly identified a South African churchman. The correct name is Beyers Naude. (Published 11/9/ 87)

SOUTH AFRICA has slid off the national screen and therefore off the national agenda. Many individuals have been "disappeared" in police states around the world, mainly in Latin America, but South Africa is the first case of a whole country to sink from public view.

Two years ago, South Africa and itssavage oppression of its black majority was a topic that generated protest even among career-struck youth on our dormant campuses. Anti-apartheid picketing of the South African Embassy on Massachusets Avenue with celebrity arrests-by-appointment was the ultimate in activist chic.

Television showed us endless, revolting footage of police attacks on unarmed blacks with dogs and whips and the destruction of their pitiful shacks.

Two things happened to erase South Africa as an issue. Congress, over the objections of President Reagan, passed sanctions, and in June 1986, South Africa declared a state of emergency.

Sheena Duncan, former president of Black Sash, an organization of white South African women who strive to bring peace and justice to their country, came to town this week to tell us that nothing has changed but our awareness of the situation. Duncan is a hearty, outspoken, fearless woman whose mother founded Black Sash in l955. The 2,500 members stand on street corners wearing black sashes to mourn the death of justice. They devote themselves to helping blacks to find their way through the trackless jungle of the restrictions and regulations which they must observe if they wish to stay out of jail.

Under the state-of-emergency censorhip laws, citizens and reporters are to avoid situations of "unrest." They must steer clear of any "gathering." A gathering to the Botha government is any assemblage of more than one person. No reporting of any gathering is permitted.

"Unrest" at universities is sternly forbidden. University authorities are held responsible for any misbehavior on the part of students or faculty on or off campus. If they fail to curb "gatherings" and other crimes, their state subsidies will be cut off. This is a serious matter because "tribal colleges' rely on the state for 80 percent of their funds.

Recently, at the University of the North, a convocation attended by the entire student body and faculty was held. The vice chancellor announced that he would resign rather than accede to conditions which would destroy academic freedom. The students apparently boiled over and marched into a nearby town, where they were set upon by police in the familiar way.

The newspapers merely reported that "to prevent violence, the police took action." South Africans learn of "unrest" only if the incidents reach the floor of Parliament. Publication of parliamentary debates is permitted. If the cases come to court, they may be reported, too. Otherwise, the South African government can continue to claim that it is making steady progress towards democracy.

Duncan reported these events to a Capitol breakfast meeting called by Rep. Sam Gejdenson (D-Conn.) to acquaint black and Jewish colleagues with the present situtation in South Africa. An Anglican, she has been given the highest award of the Union of American Hebrew Congregations, which like other Jewish organizations is bringing pressure on Israel to cease selling arms to the South African government. Israel, belatedly realizing that its cosy connection with the Afrikaans hardly becomes a nation founded on survival of prejudice and diaspora, announced it would terminate military aid; there is, however, enough in existing contracts to keep the oppressors well-armed.

Members asked Duncan what to do. She advocated more fight. American papers could print dispatches from South Africa with censored passages blacked out as they are in Africa. She wishes U.S reporters in Africa would write more analysis of public policy. The U.S. should retaliate when South Africa denies visas to inquisitive Americans. She would welcome more condemnations by public officials. They matter. Blacks, seeing U.S. intervention in Angola on the side of South Africa, are no longer sure that the United States is a model democracy. The replacement of U.S. Ambassador Herman Nickel, an enthusiast of "constructive engagement," by Edward Perkins, who actually talks to dissenters, is an improvement, she says.

Hollywood seems to be trying to fill in the blanks created by censorship. This week came "Cry Freedom," about the friendship between the young black leader Steve Biko, who was murdered by police in prison, and Donald Woods, a white editor. There was also "Cry of Reason", a documentary about Neyers Baude, the valiant, eloquent churchman.

The timidity deplored by Duncan showed up in connection with a documentary secretly made in South Africa by Walter Cronkite. Nervous CBS executives consulted a South African lawyer to find out if it would provoke the Botha government to expel CBS correspondents -- who are, of course, prevented from reporting the truth.

Not everyone has forgotten South Africa. Protesters took ads in Iowa against Robert Dole, a champion of civil rights at home who voted against South African sanctions.

Mary McGrory is a Washington Post columnist.