EVEN AS President F. W. de Klerk's white minority government and Nelson Mandela's African National Congress move closer to political talks across the color line in South Africa, violence between the ANC and another leading black claimant for power, Mangosuthu Buthelezi's Zulu-based Inkatha movement, gets worse. The battleground is widening beyond its original arena in Natal, and the death toll is measured in the thousands -- 500 lives have been lost in just the last 10 days. The fury arises in part from the sense that, with white domination easing, there is now something real for blacks to fight over. There is also, thanks to apartheid, a lack of the political habit among many of the people of the townships and homelands. Whatever the reasons, the results constitute a deep embarrassment to all who yearn for racial decency in South Africa and a serious obstacle to the building of a democratic political order.

The ANC, the country's principal black nationalist movement, is trying to ride the great surge of national and international interest in its newly liberated leader, Mr. Mandela, into political primacy. Chief Buthelezi's response has included an effort to turn Inkatha from a Zulu movement into a multiracial political party. But political tensions, exacerbated by tribal tensions, have so far kept Mr. Mandela from meeting with Mr. Buthelezi -- a step that would presumably serve social peace but would give Mr. Buthelezi more political standing than many in the ANC could stand. As for Mr. de Klerk, he is caught between the white right and the ANC: hardliners in his own community demand that he crack down harder on the violence, but the ANC suspects that he uses the police to favor Inkatha and it threatens to pull out of political dialogue with him if he reimposes emergency rule.

It was only a couple of weeks ago that, in a meeting with the Pretoria government, an ANC team led by Mr. Mandela agreed to suspend armed struggle. Events had already shriveled the ANC's capacity for political violence, but formally suspending the option had great symbolic resonance. It meant the ANC was submitting the black fate in South Africa to a political process with the former oppressor, and it gave a major boost to President de Klerk's program of negotiating a new political way. The loose ends of armed struggle have not yet been tied up. Still, to find violence among blacks increasing as the prospect of interracial violence recedes is a sobering reminder of the great distance yet to be traveled on the road to the end of apartheid.