Hardly a year after Nelson Mandela assumed the role of elder statesman, South Africans are having to adjust to a new phenomenon: sharply-worded criticism of his successor from people with no interest in unseating him.
President Thabo Mbeki is the target of attacks not only by scientific luminaries at the present international AIDS conference in Durban, but also by a softly spoken judge. Such attacks would have been unthinkable on Mr Mandela.
Perhaps there is an element of inevitability about it. Mr Mandela was protected by his status as a hero of the liberation struggle. Few people could match his ability to endure 27 years of incarceration without becoming embittered.
Mr Mbeki, however, is being judged as a mere politician. But there is more to it than that.
He is to some extent responsible for his own fate. He is a more hands-on president than Mr Mandela, more likely to intervene in the affairs of his cabinet ministers. He has largely marginalised Health Minister Manto Tshabalala-Msimang, having pronounced in a parliamentary debate that the anti-AIDS drug AZT is unsafe.
His intervention seems at times to be tainted by the zealotry and irrationality which he attributes to his opponents. In a letter to opposition leader Tony Leon, published in the Johannesburg Sunday Times at the weekend, he suggests that rape victim and journalist Charlene Smith might have been "blinded by racist rage" when she wrote that South Africa had a culture in which "rape is endemic".
Mr Mbeki accuses Ms Smith, a white woman with a track record of opposition to apartheid, of making a "deeply offensive statement" about indigenous black men, although she does not mention colour in the quotation from her article which he cites as proof of his point.
Having startled police officers last year by bluntly rejecting figures on South Africa's high incidence of rape released by their statistical specialists, he refers in his letter to Mr Leon to the "hysterical estimates of the incidence of HIV in our country and sub-Saharan Africa".
There seems little doubt that he is alluding to the latest UN AIDS report. It states that in seven southern African countries, including South Africa, one in five adults is infected with HIV.
Mr Leon offers a perspective on Mr Mbeki in his reply: "It is somewhat hypocritical to accuse overseas opinion of intolerance and then to try to shut down dissent domestically by labelling people `racists' . . . You seem more concerned with the possibility that high rape and AIDS figures might confirm the prejudices of some [people] than with the massive human tragedy in our country which those figures are merely an indication of."
Since Mr Mbeki replaced Mr Mandela as national leader of the ruling ANC in December 1997, the party has become a much more tightly controlled (and, arguably, less democratic) organisation.
Mr Mbeki has acquired and used the power to appoint provincial premiers in the seven ANC-dominated provinces.
More recently the ANC national leadership has dissolved two elected party provincial executive committees and installed interim leaders beholden to it.
Some South Africans are beginning to ponder what the wider implications are for national politics of Mr Mbeki's apparent drift towards irrational dogmatism and authoritarianism.