President Thabo Mbeki, who has led South Africa since 1999, agreed Saturday to go quietly after the ruling ANC asked him to resign. Mr. Mbeki leaves behind a largely incompetent government fraught with nepotism and corruption, and a despondent country with weakened institutions, declining education and health standards, out-of-control violence and an HIV/AIDS pandemic. Troublingly, Jacob Zuma, the man who is likely to replace Mr. Mbeki, inspires even less confidence for the future of South Africa.

To understand the disappointment of the last decade in South Africa, it is important to contrast Mr. Mbeki with his predecessor. When Nelson Mandela emerged from his 27-year incarceration, he preached forgiveness and compassion and set about to forge a nation in which the whites — his former jailers — had an important role to play. Mr. Mbeki, on the other hand, remained a Marxist ideologue who never overcame the pain and prejudices of his life in exile.

In Mr. Mbeki’s view the West oppressed the rest of mankind. Obsessed with race and colonialism, Mr. Mbeki undermined the response to the HIV/AIDS pandemic in South Africa. To him, orthodox science “portrayed black people…[as] victims of a slave mentality.” Rejection of the HIV/AIDS orthodoxy was necessary to confront “centuries-old white racist beliefs and concepts about Africans.” Hundreds of thousands, maybe millions, of South Africans died needlessly while Mr. Mbeki defended rejectionist scientists who claimed AIDS wasn’t caused by HIV.

Similarly, it was Mr. Mbeki’s warped ideology that led him to support Zimbabwe’s dictator. Robert Mugabe couched his devastating economic policies in revolutionary terms — as a just fight against alleged British plots and other delusions. For eight years the South African begged for more time for his “quiet diplomacy” while Zimbabwe burned. If the recent power-sharing deal between Mr. Mugabe and Morgan Tsvangirai works, it will do so not because of Mr. Mbeki’s diplomacy but because of his departure. Mr. Mugabe may yet find it more advantageous to compromise with Mr. Tsvangirai than to deal with Mr. Zuma who criticized Mr. Mugabe in the past.

Mr. Mbeki’ accommodating policy toward Mr. Mugabe exemplified a growing gap between the high-minded principles the South African claimed to follow in foreign affairs and the sordid reality of his policies. He cozied up to Cuba, Iran, and Libya. At the U.N., his diplomats worked with China to prevent a debate on human rights abuses in Burma. South Africa’s intelligence minister visited Iran last year, where he praised Hezbollah and Hamas. In sum, Mr. Mbeki never encountered an anti-Western tyrant he did not like.

At home, he exhibited the authoritarian tendencies he had learned during his stint in the Soviet Union. He transformed the state-owned South African Broadcasting Corporation into a personal propaganda machine that banned some of his critics from appearing on it. He banished some of his competitors in the ANC by accusing them of trying to assassinate him. External dissenters, like the opposition Democratic Alliance, were weakened by persistent accusations of racism. That stifled public debate over the direction of South Africa’s economic and social policies, including a murder rate that is nine times higher than that of the United States, and a healthcare system which according to the World Health Organization is worsening.

Mr. Mbeki was rightly praised for following good macro-economic policies that saw the budget deficit and public debt fall, and growth increase. But being reasonably tight with the public purse did not make Mr. Mbeki “business-friendly” — as he was sometimes mischaracterized. Businesses in South Africa are heavily taxed (at 35%) and regulated. They also have to follow onerous race guidelines in employment and promotion. Micro-economic over-regulation has kept growth low (expected to come in at 2% this year) and contributed to a 26% unemployment rate. The number of people living in absolute poverty has doubled since the ANC came to power in 1994.

Mr. Mbeki’s breathless drive to monopolize power has led him to attack the independence of the judiciary. According to a High Court judge, he tried to influence the judicial proceedings against his nemesis, former Deputy President Jacob Zuma. It was that apparent abuse of state power that finally gave the ANC leadership an excuse to ask Mr. Mbeki to resign.

Following Mr. Mbeki’s departure, Mr. Zuma will most likely take over after the election in 2009, while a caretaker president will run the state affairs in the meantime. But Mr. Zuma is a deeply flawed man as well. The accusations of corruption against him persist. Moreover, his judgment has been called to question. When, during his rape trial, he was asked about the wisdom of having unprotected sex with an HIV positive woman, Mr. Zuma replied that there was no problem, because he “showered” afterward.

There are also questions about his commitment to South Africa’s fragile democracy. Mr. Zuma once famously predicted that the ANC would remain in power until “Jesus comes back.” For all of Mr. Mbeki’s faults — and there were many — South Africans may yet look back at his tenure with nostalgia.