The question, says the Rev. Allan Boesak, is not whether the government will do what is necessary to bring political change -- and peace -- to South Africa. The question is whether the present government can do it.

And, he adds, in the manner of one whose mind will no longer allow him to resist an unpleasant conclusion, "I think we have to seriously reckon with the probability that this government cannot do it."

Boesak, leader of the World Alliance of Reformed Churches, father of the United Democratic Front and one of the most thoughtful, intellectually honest and troubled men you are apt to meet, is alone in his office in the "Colored" suburb of South Belville, granting what he planned as just another interview: his confiscated passport, his pending charge of "subversion" for leading a march to the prison where his hero Nelson Mandela is incarcerated, his opinion of Gatsha Buthelezi.

But for some reason -- maybe the open shirt and the blue jeans (he's officially on holiday) induce him to relax -- he decides to say baldly what so many people of all races have been reluctant to state: that state president P. W. Botha is precisely the wrong man for the job of saving South Africa.

The problem is this: the best hope for peace here is through negotiations involving authentic black leaders. At a minimum that seems to mean the unconditional release of Mandela and other political prisoners, the unbanning of the African National Congress and other liberation groups, and the return of political exiles. (Boesak believes it also would require suspension of the present constitution, at least on an interim basis.) These preliminaries constitute a single package, and it would take a major Sadat-like leap of faith for a state president to implement them.

But Botha's cautious political style -- one tested step at a time -- seems to be the exact opposite of what is required. His tiny, always-too-late concessions are met with contempt by blacks and with alarm by his own right wing. His caution, in a situation calling for bold statesmanship, only buys him trouble and makes him that much more reluctant to try anything bold. Frustrated, he keeps turning to the only thing he seems to have confidence in: more repression.

But the harsh repression that halted earlier liberation drives (riots, as he saw them) does not appear to be working this time. The emergency measures may be keeping the battles off the air waves, but it has not kept them off the township streets. And Botha doesn't seem to know what else to do.

So what is the way out? Boesak's answer is that white South Africans must be made to understand that it is in their interest that Botha be replaced.

And soon. "I really think that we are in what one could call a decisive phase of the struggle. It's not the final phase yet, but it is the phase that will determine whether constructive change is possible. If it doesn't happen by the turn of the century, if it isn't clearly under way by 1990, it will never happen."

But that doesn't mean that whites would be well advised to try to cling to power while waiting for the liberation struggle to exhaust itself. The alternative to a failed liberation effort is not continued white dominance but the ungovernability of the country, Boesak believes.

"People who think that we'll be going from here to some kind of Angola or a Zimbabwe situation are making a mistake," he says. "I think South Africa is moving toward a Lebanon situation, and that is truly frightening.

"Why do I say this? We have a generation of kids of 8 and 9 and 10 and 15 who are being jailed, who are being brutalized by the police, who have been tortured, who have seen their little friends shot to death for no reason at all, who have experienced the violence, the tear gas and the guns. What will those kids be like come 1990 and the situation hasn't changed?

"The damage that we do to our kids -- we have a whole generation of children who in 10 years will look back and find that they have never been children. They will have missed out on that essential thing of being a carefree child, with not a single worry in the world, which I think is very, very vital for any person to become a well-balanced grown-up capable of making responsible decisions. Our kids don't have that.

"It is not cute when mothers bring me their 4-year-olds who, when they see me or my picture, stand with their fist in the air and shout 'Amandla!' (Xhosa for 'Power!') or 'Vive Boesak!' It is not a compliment. I know they mean well, but what in the world are we doing with our 4-year-old kids? By the time they are 6 or 7 or 8, they have grown accustomed to Casspirs (armored personnel carriers used by the security forces) and police vehicles, and they know by then how to react to these people. When they are 15, they may be able to make petrol bombs and to throw them, but what does that do to our children?

"These are the things that I think are absolutely frightening. And if the South African government thinks that it can continue with its violence and this undeclared civil war that is being waged not only on our people but more especially on our children, without somewhere reaping the whirlwind, it is making a very, very fundamental mistake."

Boesak apologizes for sounding so pessimistic when so many encouraging things are happening. "Look at the determination of our people, the unity, the incredible solidarity, the courage -- the father that buries his second child but who gets up at the funeral to say, 'I am burying my second child killed by the police, but let me say, let them send their thousands, let them send their 10 thousands; we will not stop till we have what we want.' That I find intensely moving, and I am very grateful for that. But then I think of the other repercussions, I think of the children. . . .

"I don't think we can hide this any longer. We have got to find a way of getting rid of the present government as soon as possible. Whites will have to do that, and the outside world will have to help. Something must happen, and I mean in the very, very short term."