JOHANNESBURG — THE euphoria that followed the unbanning of the African National Congress and the release of Nelson Mandela six weeks ago has given way recently to doubts about the ANC's power and Mr. Mandela's authority in the townships. A renewed wave of violence in black areas - which has already claimed more than 250 lives - has raised fears that neither the government nor the ANC is able to control it.
During the first two weeks of March, the violence matched the level of conflict in the 1984-85 nationwide rebellion in black townships.
This has highlighted the urgency of the first scheduled talks April 11 between a Mandela-led ANC delegation and a government team headed by President Frederik de Klerk.
``The government and the ANC need each other to control their troops on the ground,'' says Mark Swilling, a political analyst at the independent Center of Policy Studies. ``Neither side can do it unilaterally; but they share a growing need to end the violence.''
This rapid convergence of interests between Pretoria and the ANC is the major force keeping the negotiating process on track, despite a deteriorating political environment.
The resurgence of violence in the townships is likely to feature prominently at the April meeting, which the government hopes will set the scene for negotiations leading to a cessation of hostilities.
This would involve the government lifting the 41-month-old nationwide emergency and a general amnesty for exiles and prisoners in exchange for the ANC suspending its 28-year-old ``armed struggle.''
But the spiraling violence makes the imminent lifting of the emergency unlikely.
The government acknowledged the urgency of raising the socioeconomic standard of blacks last week when it announced a $1.2 million fund to begin closing the gap between black and white education and housing.
But critics of the ANC feel it has done little to match Mr. De Klerk's gestures and note that Mandela's repeated calls for peace appear to have been unheeded.
Mandela returned to South Africa at the weekend after a three-week foreign visit. But only one-tenth of an expected crowd of 100,000 turned up to hear the cream of South Africa's pop musicians welcome him home Saturday.
At a news conference on his return, Mandela described the violence as ``unfortunate'' but added that the uprisings in the tribal homelands showed that the ``masses'' rejected apartheid rule.
Mandela said that, once he had received a full report from ANC leaders inside the country, ``action'' would be taken.
But serious doubts are emerging about Mandela's capacity to end the violence and the ANC's ability to enforce his calls. This could weaken the ANC's position at the negotiating table.
``Already it is plain - even to outsiders - that Nelson Mandela does not control the black people of South Africa. His authority is tenuous and limited,'' writes Ken Owen, editor of Business Day, a financial daily.
Some anti-apartheid activists now accept that it will take months - or even years - of grass-roots organization to transform the ANC into a sound and disciplined political party.
But both sides appear to realize that results have to be achieved quickly if negotiations are to have any chance of success.
``Our strategy is that the very first meeting must produce a result,'' Mandela said last week.
The township violence seems to be - in part - a delayed reaction to hopes created by Mandela's release but since dashed. There is evidence in some areas that the rival Pan Africanist Congress is gaining ground on its hard-line platform of ``no compromise.''
For the average township resident - beset by the specter of poverty, unemployment, and violence - there have been no tangible benefits to match the political euphoria of Mandela's release.
``One of Mandela's big mistakes is to have made public calls for peace without ensuring that mechanisms are in place to implement the calls,'' says Swilling. ``It makes him look like a loser.''
Western diplomats, eager to avoid derailment of the negotiating process, were puzzled by Mandela's call from Sweden last week for the international community to sever all diplomatic ties with Pretoria.
``One would have thought Mr. Mandela would have been sufficiently astute not to call for something which is so obviously not going to succeed,'' says a Western diplomat.
Some analysts believe the calls by Mandela reflect the hard-line position of influential anti-apartheid leaders inside the country like mineworkers' boss Cyril Ramaphosa.
The diplomats believe that this hard line may also explain Mandela's public criticism of United States Secretary of State James Baker III's planned meeting with De Klerk in Cape Town Thursday, following Namibia's independence celebrations. (See story, Page 5.)
Mandela said he would meet Mr. Baker outside South Africa - presumably in the Namibian capital of Windhoek - ``if he wants to see me.''
While some of the recent township violence has been between black communities and security forces, there has been a growing trend toward internalized violence between opposing black factions.
Sporadic and factional violence which has erupted in Transvaal townships like Katlehong - where at least 30 people have been killed - bears many of the hallmarks of the 1984-86 rebellion.
The macabre ``necklace'' - a gasoline-soaked tire placed around the victims neck and ignited - has returned and so have mob killings and the crude justice of ``people's courts.''
``As each day passes, the choice between violence and peace becomes ever starker,'' says Swilling. ``But there is still time to negotiate before all hell breaks loose.''