Johannesburg — Quietly, the way Edward Perkins prefers to do things, the new American ambassador to South Africa is overseeing a shift in the United States' approach to the political conflict here. On the surface, little has changed in American policy. Thus the State Department had little trouble ``clarifying'' recent public comments by Mr. Perkins which some analysts - notably, in South Africa - construed as a sudden break with Reagan administration opposition to economic sanctions against Pretoria.
A State Department spokeswoman suggested that the ambassador's remarks, made during a home-leave appearance last week in Oregon, had been taken out of context.
Yes, Perkins said that the sanctions enacted by Congress over President Reagan's protest had been a ``success'' - in conveying American moral outrage. Yet, the spokeswoman noted, Perkins added that sanctions had not yet shown signs of reaching their presumed ultimate goal: to ``end apartheid.''
But a quieter subtheme in Perkin's speech - as in his diplomacy since arriving as Washington's first black ambassador here last year - was that the US must find ways to distance itself far more than in recent years from official South African policies.
In a passage in the Oregon speech given far less media attention than his sanctions remarks, Perkins cited the need for ``more inventive ways to manage our relationship with the government of South Africa and with the South African people.
``We have to make abundantly clear in almost any way we can our abhorrence of a system which has a minority of the population enjoying economic and political rights at the expense of the majority,'' he was quoted as saying.
The tone of Perkins remarks is tougher and less equivocal than that set by Mr. Reagan in the early part of his administration. Reagan's policy - which has come to be known as ``constructive engagement'' - played down the need for public shows of disapproval, stressing quiet persuasion with the South African government. But Congress's defiant sanctions vote last year left Reagan's policy badly hobbled.
In South Africa, where Perkins is due to return early next month, he has embarked on an exercise in quiet diplomacy consistent with his Oregon speech. He has granted no press interviews to local or American reporters. His aides have adopted a similarly silent approach. But with apparently far greater success than his predecessor, Herman Nickel, Perkins has been striving to build bridges with key actors on all sides of the South African political spectrum.
Through private meetings with black critics of the South African government, he has been moving to change the image of the US here. Where until recently Washington had been closely identified with Pretoria, the evident hope is that it will come to be seen as a more ``disengaged'' party intent on dialogue with all sides, official and opposition.
In this aim, Western diplomats here are convinced that Perkins is acting in full concert with the State Department - and at least the tacit OK of a Reagan administration with little to gain by allowing ``constructive engagement'' to emerge as a major Democratic Party issue in the forthcoming presidential election campaign.
Journalists in South Africa operate under official press restrictions.