Nine years ago, Thabo Mbeki became the second democratically elected President of South Africa. He had been the heir-apparent of Nelson Mandela since the murder of Chris Hani, the leader of the military wing of the African National Congress, by a right-wing fanatic in 1993.

As Mr Mbeki now prepares to depart the presidency, the measure of South Africa's achievement since the vanquishing of apartheid may be marked by that assassination. Few expected the transition from a white supremacist oligarchy to a non-racial democracy to be accomplished peacefully, and for South Africa to develop as a constitutional state. What Mr Mandela fashioned, after Afrikaner nationalism had belatedly acknowledged its ideological exhaustion, Mr Mbeki has at least preserved.

In 14 years since Mr Mandela's election, the ANC has eschewed retribution and advanced the processes of the Truth and Reconciliation Commission. It is a minimal point of comparison - but the victims of the oppression and penury wreaked by Robert Mugabe in Zimbabwe would scarcely be able to imagine government as it has been practised across the Limpopo. Yet these achievements exist in South Africa despite Mr Mbeki rather than because of him. Any leader would have been overshadowed by the mantle of Mr Mandela. Mr Mbeki, however, has tarnished his political inheritance and weakened South Africa's moral authority. Even at the level of rhetoric, Mr Mbeki has failed to understand the force of Mr Mandela's invocation of a “rainbow nation”. Mr Mbeki has instead repeatedly spoken of “two nations, one white, one black” - and he has failed the second.

The greatest domestic indictments are mass unemployment (more than 25 per cent) and poverty. Expanding transfer payments, which now account for around 3 per cent of national income, have not remedied South Africa's extreme social inequality. The most direct way of tackling the social question is to allow business to expand, create jobs and generate wealth. The government sector has proved inefficient in promoting development and meeting basic needs. And Mr Mbeki has weakened South Africa's reputation for welcoming inward investment - even while the country faces an energy crisis and economically crippling power cuts.

Beyond the economic malaise, Mr Mbeki has failed South Africa in two signal ways that have outraged international opinion. First, his insistence on the principle of national sovereignty has been widely interpreted as collusion with the tyranny of Mr Mugabe. At the very least, Mr Mbeki has not fulfilled the stablising regional role that South Africa ought to play. Secondly, his preposterous pseudoscientific denial that HIV causes Aids has had terrible consequences for public health in a nation that has the highest number of carriers of the virus.

It can at least be said of Mr Mbeki that, after allegedly interfering in the corruption case against his rival, Jacob Zuma, nothing in his presidency becomes him like the leaving of it. He has accepted the rule of law; and in relinquishing the presidency, he has yielded to the inevitable. Of his likely successor, initial signs are mixed, but include a discouraging tendency to economic populism. On succeeding to the presidency, Mr Zuma will have much work to do.