JOHANNESBURG, FEB. 16 -- The criminal trial of Winnie Mandela, which was postponed this week until early March, has led some white liberals to question the African National Congress's commitment to the impartial administration of justice in "the new South Africa."

Her trial on kidnapping and assault charges has been marked so far by the mysterious disappearance of four co-defendants and a key prosecution witness and the refusal of the prosecution's two remaining witnesses to testify. The ANC has argued that the trial is a political attack on the wife of its leader, Nelson Mandela,and that she is the harassed victim of the apartheid system of racial separation.

After two weeks of off-again, on-again sessions, a sense of nascent farce and tragedy hung heavy in the courtroom. Even some of South Africa's white anti-apartheid crusaders, who have long decried the inequities of justice under the white minority government, have started ringing alarm bells.

"Is this rule by Toyi-Toyi Macoute?" asked the liberal Weekly Mail in a play on words combining the name of the street dance of ANC supporters with Ton-tons Macoutes, the private army that enforced the rule of former Haitian dictator Francois Duvalier.

"So far, the only clear victim is justice," said the Weekly Mail editorial. "So far, the only thing that has been proven is that there is grave cause for concern about the ANC's attitude to justice and the legal system."

The prosecution centered its case against Winnie Mandela on three witnesses ready to testify against her for allegedly taking part in kidnapping and assaulting them and a fourth black, 14-year-old "Stompie" Moketsi Seipei, on the night of Dec. 29, 1988. Seipei was found dead three days later.

The prosecution witnesses already had helped convict one of Mandela's former bodyguards, Jerry Richardson, of the youth's murder, and in the course of their testimony against him last May provided graphic details about Mandela's alleged participation in their abduction from a Soweto church and their beating at her home. Mandela was not charged in Seipei's death and did not appear as a witness at Richardson's trial, on her lawyers' advice.

Nelson Mandela, who was in prison at the time of the incident but was released three months before the Richardson trial, publicly fumed when his wife's name came up again and again in testimony against her former bodyguard. Mandela objected that his wife was being publicly indicted and was accorded no right to reply or defend herself.

He then virtually challenged the state to charge her. He accused the state prosecution of "deliberately not charging" Winnie Mandela in an attempt to "besmirch my wife's reputation" in the press "before she is even found guilty."

"When my wife is not charged and the whole case centers on her, she has no way of defending herself and establishing her innocence," he said.

In September, the state obliged, indicting Winnie Mandela and seven co-defendants on four counts of kidnapping and four counts of assault.

The ANC initially considered her case a personal matter and said it did not seek "any special treatment" for her except an end to her "trial through the media." When Winnie Mandela showed up in court Sept. 24 to be formally charged, her husband was the only ANC official to accompany her.

But as the Feb. 4 trial date approached, the tone of both Nelson Mandela and ANC officialdom changed noticeably. A Jan. 25 ANC statement signed by its secretary general, Alfred Nzo, said the trial was "part of a pattern of harassment and persecution" of Winnie Mandela by the state and police over the past 30 years. It was a "political trial," said the statement, which called for an end to the "blatant harassment of the ANC."

Meanwhile, four of her co-defendants had failed to report to the police since December, as they were required under bail arrangements. This did not become public knowledge until Feb. 4, when they failed to show up for the first day of the trial.

What appeared in their absence was the first hint that here was a farce in the making. The Sunday Times told of how Katiza Cebekhulu, one of the four bail-jumpers, had actually been on the steps outside the Supreme Court building in downtown Johannesburg watching Winnie Mandela and the others go in that first day. No police officer recognized him, but a reporter did.

"I just wanted to see what was going on," he told the newspaper.

The ANC, in a show of support and solidarity for Winnie Mandela during what it was now calling a political trial, sent its senior leadership into court, including Nzo, Joe Slovo, who also is the Communist Party secretary general, and Chris Hani, the ANC's military chief of staff.

After a week of technical arguments and defense attempts to quash the charges, the trial was finally set to get underway last Monday. That day, the state prosecutor shocked the court with an announcement that his first witness, Gabriel Mekgwe, had disappeared from the same church in Soweto from which he had allegedly been kidnapped in 1988. The Star newspaper said it had reliable sources claiming Mekgwe had left the church with "three ANC men."

The plot thickened when a person claiming to be Mekgwe began making telephone calls to Johannesburg newspapers from Harare, Zimbabwe, saying he was alive and well and ready to talk to the state prosecutor -- but only outside South Africa.

The other two witnesses, scared out of their wits by Mekgwe's alleged kidnapping, refused to testify, even in the face of five years in jail. The judge postponed the trial.

One person involved in the drama, who asked that he not be named because he feared that his and other lives were at stake, said the trial of Winnie Mandela seemed "a Greek tragedy," in which the outcome is known beforehand and both players and audience can only watch helplessly as the tragedy unfolds.

In this trial, he said, the tragic figure is justice in the "new South Africa" -- and the outcome, Winnie Mandela's escape from the witness stand, is already known.