BLACKS and whites in South Africa have endured an abrasive and often bloodstained relationship since the Dutch first established a trading post at Cape Town in 1652. That story has now taken on a new dimension. But first, some background.
Throughout the 18th and 19th centuries the black-white relationship in South Africa was typical of that which prevailed in most places where white Europeans established a colonial overlordship with the native blacks, providing cheap labor.
The relationship took on a unique character in 1948 when a new government dominated by Afrikaners (Boers) launched a policy of ''apartheid.'' It called for separate development of black and white races.
It might have worked had the South African whites been willing to carry it out literally and totally. They could have divided the good farmland and the gold and the diamond mines fairly between the races. The whites could have separated themselves totally from the blacks, and each gone their own way.
But that would have meant the whites giving up cheap black labor. They did not push apartheid to that logical conclusion. Instead they pushed blacks who were surplus to the labor needs of the white community into ''tribal homelands, '' usually not containing much good cropland, and never containing gold or diamond mines. Those blacks wanted for labor were pushed into black townships in commuting distance from jobs in the white communities.
Tension between whites and blacks has been mounting ever since. It burst again on Sept. 3. That was the inauguration day for a new constitution under which Indians and ''Coloreds'' (persons of mixed blood), but not blacks, were given political representation.
It was the worst rioting since 1976. The death toll was put by police at 29. There were further riots in Soweto, near Johannesburg, on Sept. 12, the seventh anniversary of the killing by police of prominent black leader Steve Biko.
Another dimension was added Nov. 5 and 6. For the first time in South Africa, blacks organized a massive two day work stoppage. An estimated 800,000 blacks stayed home. Whites had their first taste of what it would be like if no black labor was to be had.
Police retaliated by arresting 16 of the leaders of the black labor organizations. That in turn added still another new dimension to the long and troubled story of black-white relations in South Africa.
This triggered a higher level of protest in the US against South Africa's policies. Sustained demonstrations have taken place outside the South African embassy in Washington and South African missions in other cities. Five states and 11 cities have passed laws against state and city pension funds holding shares in companies doing business in South Africa.
Many whites and representatives of white organizations, including the AFL-CIO , have joined in the protests. Perhaps most significant politically is a letter to President Reagan signed by Sen. Richard Lugar (R), the new chairman of the Senate's Foreign Relations Committee, and Sen. Nancy Kassebaum, chairman of its subcommittee on Africa. The letter urged the President to speak out more strongly against apartheid. Also, 35 Republicans joined to warn the President and South Africa that they may work for economic sanctions against South Africa.
President Reagan received Anglican Bishop Desmond Tutu, a black, at the White House on Dec. 7, but said he would continue to pursue an American policy of ''constructive engagement.'' He claimed credit for the release by South Africa of 11 of the leaders of the Nov. 5-6 work stoppage. Five others are still in jail and to be tried for alleged subversion.
The white South African government assumed that reelection of President Reagan would mean continued tacit acceptance in Washington of their apartheid policy. But that assumption overlooked the reaction in the US to the arrest of the labor leaders. The race issue in South Africa is an old story in new dimensions.