Johannesburg — South Africa's ruling National Party is taking the offensive against increasingly assertive defectors from its right flank. The opening salvo has come in the form of the party's denunciation of several recent white vigilante attacks against unarmed blacks, and the party's defense of government plans for race-policy reforms. This broadside appears in the current issue of the National Party's magazine.
It comes as President Pieter W. Botha is putting final touches on a bill to abolish the ``pass law'' system, which regulates where blacks are allowed to live and work. Officials have indicated that the bill could be presented within the next few weeks. It would be the largest step yet away from apartheid, the network of racial segregation laws erected by previous National Party governments.
To most black leaders, the reforms announced so far have been a case of too little, too late. Blacks are also skeptical about the pledge to scrap the pass system. They note that Mr. Botha's parallel emphasis on ``orderly urbanization'' could mean the reintroduction of present restrictions under some other name.
The liberal opposition Progressive Federal Party in Parliament, where the National Party retains an overwhelming majority, has also expressed skepticism about Botha's program. The opposition's leader, Frederik Van Zyl Slabbert, resigned in February, saying he had no hope Botha would move significantly to meet black political demands.
Yet the reforms have already gone far enough to provoke a split in Botha's party as well as fuel support for several new groups on the extreme right. A change in pass laws could increase support for extreme conservatives, who charge that Botha is risking a wholesale political takeover by the country's black majority.
The National Party seems concerned on two counts.
First is the danger of an increase in the violent white backlash against blacks. Second is the prospect of a conservative political backlash that could ultimately erode the party's dominance of white politics. As it now stands, the next national election is set for 1989.
White-on-black violence became a highly visible problem starting in February with several attacks on blacks in the Transvaal, heartland of conservative political strength and a traditional National Party base.
There were incidents of apparently random gunfire on blacks. Police charge that in another attack a group of whites burned a black man alive.
Denouncing the violence, the editorial on the front page of the National Party magazine said such activity plays into the hands of black extremists. These people, the magazine said, ``want white fears to turn to rage so that peaceful coexistence . . . becomes impossible.''
The alternative, said the editorial, would be civil war, which ``neither South Africa nor the whites can survive.''
The article decried whites who ``want to take the law into their own hands by deliberately shooting at innocent black people, as has already happened.''
There were, the rebuttal made clear, political effects from such a backlash as well. Singled out for criticism were two extremist groups that have taken root since Botha came to power as Prime Minister in 1978.
The first is the National Conservative Party of Andries Treurnicht.
He was the National Party's Transvaal chief until 1982 -- when he split and formed his own party with other disaffected National Party parliamentarians.
The Conservative Party is the second-largest opposition group. It has made no secret of its hope to displace the liberals as the official opposition in the wake of their party leader's resignation.
Also cited in the National Party broadside was the extraparliamentary Afrikaner Reistance Movement -- or AWB -- of Eugene Terre Blanche, a native of the rural Transvaal who is a powerful stump orator. Mr. Blanche feels Botha's policies are leading the country into the civil strife between whites and nonwhites.
When that occurs, he has warned, true nationalists will retake control by force.
``Thousands of whites flock to AWB meetings to revel with glee in the emotional racial hatred which gets fanned there,'' the National Party's article lamented. The Conservative Party, it charged, ``condones these excesses and wishes to enter an alliance with the AWB.''
But the magazine said the two groups were becoming the ``usable idiots'' to which Vladimir Lenin referred in his revolution theories.
``That is the road of white suicide in South Africa.''
Arguing that moderates are still in the majority, the editorial said their best bet lay with the reforms outlined by the government.