PRETORIA, SOUTH AFRICA, OCT. 20 -- Ever since its formation 76 years ago, South Africa's National Party has been dedicated to the idea of white racial exclusivity. But in the seven weeks since President Frederik W. de Klerk first suggested that the party prepare for "the new South Africa" by opening its ranks to black members, there has been a mass conversion to the idea of racial integration.

And not just by most Nationalists, but by nearly all of them. The last of the ruling party's four provincial conventions, which ended here today in deeply conservative Transvaal Province, gave its unanimous endorsement to the president's idea, as did the Cape and Natal conventions. Only in the province of Orange Free State, where three dissenting votes were cast, was there any questioning of this renunciation of the party's most fundamental principle.

The Transvaal delegates gave the endorsement of an open party a standing ovation. Speech after speech from the convention floor showered praise on de Klerk and his vision of "the new South Africa."

The phrase is on everyone's lips. It is emblazoned on banners and posters, even stamped on bottles of wine, bearing pictures of Nationalist leaders, that were sold at the convention to raise money for the party.

But it was not apparent from speeches from the convention floor, or in conversations with party members during breaks that these recent converts to the idea of a "new South Africa" fully understand what the phrase implies -- the possible end to 42 years of rule by their kith and kin, and perhaps even life under a black government.

The speeches and comments indicated that the appeal of "the new South Africa" is more that of a catch phrase that seems to be bringing this nation in from the cold, getting its ostracized president invited to the White House and Downing Street and opening up the prospect of sanctions being lifted and perhaps even a return to international sports.

De Klerk was hailed for all these things, but not for opening up the possibility that he may have to hand over power to a black president -- a thought that, if it occurred to anyone, was never mentioned.

In his speeches, de Klerk makes a small addition to the slogan. He speaks of "the new, just South Africa." But if that implies that the old South Africa was in any way unjust, he does not say so. It is another feature of this mass conversion that it is not accompanied by any suggestion that apartheid may have been immoral. Apartheid may have been a political mistake, a policy that proved to be unworkable, but that is as far as the discussion goes.

As Information Minister Stoffel van der Merwe put it when asked at a news conference to explain the wholesale acceptance of the party's policy turnaround: "The idea of a just society is not new to the Afrikaner. That was our motive for trying to have separate states for the different races, and when it proved to be unattainable the search for justice remained."

The Transvaal leader, Finance Minister Barend du Plessis, made the same point in his wrap-up speech today. After declaring that the triumph of the convention was that it had given rise to "a liberated National Party that is now operating on a moral basis," he paused a moment to ask: "Is there implicit in that an accusation that our predecessors were not moral, that they were unjust?

"Absolutely not," was his reply. "The truth is that if it had been possible to divide this country so that the whites could be a majority and the blacks had their own sovereign states, then we would have been able to escape that way from the accusation of discrimination and injustice.

"But over a long period of time it became clear that total segregation was not possible, and with that we realized that we had to change course and that power-sharing was the only way for us to go."

Piet Cillie, the doyen of Afrikaans-language journalists, put it another way. He wrote recently that it had been necessary to pursue the apartheid policy of racial separation in order to demonstrate that it was unworkable. Only then could the change take place.

In none of these statements has there been any mention of the 18 million black pass-law arrests and 3.5 million forced removals that the experiment required.

De Klerk has sometimes been compared with Mikhail Gorbachev for the way he has tried to liberalize a failed authoritarian system, but there is one important difference. South Africa has had no equivalent of de-Stalinization. Hendrik F. Verwoerd, the prime minister of the 1960s who was the chief architect and implementer of apartheid, remains an honored figure.

This has led to a certain schizophrenia among loyal party followers that revealed itself from time to time at the conventions.

For example, Julie Coetzer, of the Women's Action group, spoke on Friday of the "wonderful new spirit" infusing the National Party as a result of de Klerk's reforms.

"It reminds me," she said, "of when I was a young girl and the wonderful spirit I felt when I joined the crowd at the airport to welcome Verwoerd back from the Commonwealth conference in London." She was referring to 1961, when South Africa left the multiracial Commonwealth of former British colonies rather than abandon apartheid as the black member states demanded. It was the high point of Afrikaner nationalist chauvinism.

Then there was Willie Breedt, an elderly delegate from a Transvaal country town. "I welcome this move {opening the party to blacks} because it is the right thing to do," he said. "We in the National Party have always done what was right, even when it was unpopular."

At the Cape congress two weeks ago Frikkie Botha, of Queenstown, applauded the idea of "the new South Africa" -- while proposing that there be a new law entitling the police to shoot any black person who picked up a stone to throw at them.

Another Cape delegate pleaded for a law in "the new South Africa," which he also endorsed, that would enable the police to get rid of blacks in small towns "who are not actually committing any crime but are being, shall we say, a nuisance."