Johannesburg — Why would a privileged white Afrikaner turn against the government of South Africa and join forces with the outlawed African National Congress? How could a self-avowed Christian come to accept violence as the only means of changing South Africa?
Carl Niehaus, a bearded 23-year-old, tried to explain his political transformation as he stood before the judge who had convicted him and his girlfriend of high treason.
Mr. Niehaus's words went well beyond the confines of the packed courtroom. In this security-conscious society, a white who breaks rank and joins the ''black struggle'' is a subject of hostility, puzzlement, and considerable interest. Also, court proceedings provide a first-rate chance for the open airing of subjects - such as the aims and motives of the African National Congress (ANC) - that are severely circumscribed under normal censorship restraints.
Late last week Niehaus was sentenced to 15 years. His girlfriend, Johanna Lourens, was sent to jail for four years for acts of treason. Niehaus greeted the sentence with a defiant cry of ''amandla,'' Zulu for power.
His earlier testimony showed his support for the ANC, although its violent tactics had caused ''quite a lot of turmoil in my soul,'' he said.
''Initially I was very concerned about the use of violence. On one side there is the violence which is institutionalized in South African society. On the other side there is the kind of violence employed by the ANC,'' he said.
''It is not that the ANC enjoys exploding bombs. It has been forced to it by the South African government and as long as the situation goes on, bombs will continue to explode. . . .''
Niehaus was convicted of a number of acts meant to further the aims of the ANC. Both he and Ms. Lourens pleaded not guilty to treason, although he openly stated that he is an active supporter of the ANC. Niehaus admitted once placing a pamphlet bomb outside the door of an Army recruiting office in downtown Johannesburg. He used strong language in describing a situation in South Africa that he felt called for violent tactics.
''I would like to draw a parallel with Nazi Germany,'' he told the judge. He made specific reference to ''. . .innocent people dying in the homelands'' - the impoverished rural areas where many of South Africa's blacks are forced to live.
The son of a traditional Afrikaans-speaking family, Niehaus grew up as a member of the conservative Dutch Reformed Church, whose doctrines support apartheid. He began to study theology at the Rand Afrikaans University, but budding political interest soon sidetracked his studies. He was expelled for political activities that included putting up posters calling for the release from prison of ANC leader Nelson Mandela.
Niehaus eventually rejected the white Dutch Reformed Church, joined the black sister church, and worked for a black congregation in Alexandra, a township on the outskirts of Johannesburg.
''I call it a privilege to have seen what life (in the townships) is really about. Most people in South Africa lead lives of luxury and support policies which hurt others terribly, simply because they don't know what the conditions are,'' he told the court.
The state had clearly made a major target of Niehaus. Much of its evidence was methodically gathered by a housemate who turned out to be an undercover security policeman.
Niehaus could have been given the death sentence. But in explaining the softer sentence, the judge said he hoped Niehaus would be rehabilitated and that ''with the passing of time he will grow out of this phase.''
However, when the prosecutor asked how he would act when released from jail someday, Niehaus replied, ''my attitude would remain exactly the same.''