Ciskei has horrified those who must carry responsibility, except perhaps the primary culprit, Brigadier Oupa Gqozo. Suddenly the abyss yawned. In response, Pretoria has conceded the ANC's view that there can be no further progress to the 'new' South Africa until violence is addressed seriously. Until now Pretoria has treated the killings as a political football. It is not the government's supporters who are dying; and pinning the violence on the ANC reinforced President F W de Klerk's assertion that the organisation was unfit to govern.
The Ciskei tragedy forced the ANC to contemplate scaling down the more confrontational aspects of mass action, and to curb the burgeoning influence of its more radical leaders. The result is Thursday night's concession by the ANC which lays the groundwork for the first summit meeting between Mr Mandela and Mr de Klerk since April when negotiations stalled over constitutional differences. These have largely been resolved, but the Boipatong massacre scuppered a resumption of talks until the question of violence was addressed.
So why is the aftermath of Ciskei different from the earlier massacres? For one thing, it was visible. Many of of those killed in the past two years had no clear political allegiance. They were often killed asleep in their beds by mysterious men who melted away into the night. In Bisho, in full view of the television cameras, no one was in any doubt about who the perpetrators and victims were. It was a stand-off between the liberation movement and the security forces reminiscent of the P W Botha years, or even further back. Ciskei was the largest mass killing of demonstrators since 69 died at Sharpeville in 1961. It was like looking back and seeing the future.
The spectre of South Africa sinking back into such set-piece confrontations shocked both sides into getting talks going again, even if a few preliminaries still have to be sorted out to save face.
The government used the Communist Party's role in pressing the confrontation with Brigadier Gqozo to launch a wider attack on the party's influence in the ANC. But Mr de Klerk must shoulder some responsibility for the rising influence in recent months of the party members and sympathisers who favour stalling negotiations until the mass action campaign weakened the government's hand.
Pretoria's cynical manipulation of the violence, and its failure to curb the security forces, hardened attitudes in the townships against talks. The Ciskei massacre may have quenched the thirst for confrontation among the ANC's young township supporters, but this will not last if the government does not heed some of the demands made by Mr Mandela to stop the slaughter.
Pretoria's consistent refusal to implement measures such as a ban on carrying weapons in public - a recommendation by the Goldstone commission into violence, whose report the government accepted - is interpreted by opponents as a gesture of support for the killing. The government has partially met some demands - by, for instance, upgrading some migrant hostels and ejecting those responsible for attacks on township residents. But it does so quietly for fear of being seen to surrender to pressure.
The carnage at Bisho has given a breathing space to those, such as the ANC's Secretary-General, Cyril Ramaphosa, who favour resuming talks with the government. On Wednesday Mr Ramaphosa virtually rejected a summit meeting between Mr Mandela and Mr de Klerk. On Thursday, after a leadership meeting at which the ANC moderates came to the fore once again, he proposed preparatory talks that can reasonably be expected to produce such a meeting within the month.