When Mandela was elected as the first black head of state 20 years ago, there were massive problems to be faced. But there was also massive hope in South Africa, where transition from the old race-based order to a new democratic age had been achieved without descent into civil war.
Some described the transition as a miracle, although it was in fact a hard-headed realpolitik compromise between Mandela's African National Congress (ANC), which knew it could never win an armed struggle, and the white-dominated ruling National Party, which realised that permanent suppression of the black majority would ultimately destroy the country.
The absence of Mandela "magic" - against a background of growing government corruption under current President Jacob Zuma - makes this the most crucial of the five general elections held since Mandela took his oath of office on May 10, 1994, saying: "Let there be peace for all. Let there be work, bread, water and salt for all. We pledge ourselves to liberate all our people from the continuing bondage of poverty, deprivation, suffering, gender and other discrimination."
The hope of two decades ago has been replaced by a more cynical and critical mood in a country where the official unemployment rate is more than 25%, but where the figure has reached 50% among South Africans aged 19 to 25, the so-called "born-free" generation, who have grown up in the post-apartheid era. These youngsters comprise one-quarter of the voting population: how they vote will decide how powerful or weakened the post-Mandela ANC will emerge from Wednesday's election.
In an entirely proportional-representation election to the 400-seat National Assembly, the ANC share of the vote is universally predicted to be well down on the 70% share it claimed at the peak of its popularity 10 years ago.
Hardly anyone foresees the ANC failing to win more than 50% of the vote, but if its share drops below 60% tremors of uncertainty will reverberate through the ranks of Mandela's successors, who have been subjected to unprecedented criticism for their self-enrichment and failure to live up to the Mandela pledge to liberate the people from poverty and deprivation.
Under Zuma - the ANC's former head of counter-intelligence who was known and feared among guerrilla soldiers as "imbokodo" (The Grindstone) when the party was in exile in Zambia - the ANC government has reached a tipping point. Economic growth has stagnated and, in a significant but little-noted development, Nigeria passed South Africa as the continent's biggest economy two months ago.
As well as the high rate of unemployment, poor education and health systems still hold back many black people. The police, though no longer dominated by whites, are still brutal. The August 2012 Marikana Massacre, in which 34 striking miners were shot dead and 80 wounded by police, has been compared to the 1960 Sharpeville Massacre in which apartheid police shot dead 69 blacks protesting against notorious pass laws, an internal colour-based passport system, triggering a storm of international protest and the formation by a young Nelson Mandela of Umkhonto we Sizwe (Spear of the Nation), the military wing of the ANC. In both massacres fleeing victims were shot in the back.
Zuma and the police have refused to accept anything approaching responsibility for Marikana, much as apartheid security forces refused to be held accountable for Sharpeville. An official Marikana inquiry has dragged on for more than a year. Not one policeman has been charged in connection with the killings, but workers who were shot and survived have been charged.
Last week President Zuma cancelled a visit to Marikana, fearing assault by 4000 miners and relatives of the dead. "We do not want to give anarchists a platform to advance their agenda," said a Zuma spokesman.
Wanton force by today's police has become habitual in response to expressions of mass unhappiness and civic unrest. In one particularly brutal police action, a Mozambican immigrant was dragged in chains and handcuffs behind a police vehicle until he died. Police immunity has stoked a cynical view that there are two types of justice - one for rich and connected South Africans and one for everyone else. The astonishing display of state resources dedicated to the trial for murder of Olympic "blade runner" Oscar Pistorius has only reinforced this view.
While it is true that life has gradually improved for many in the years since apartheid ended, notably in housing and in the supply of running water and electricity, many problems common in the old era remain. And although millions of tiny houses have been built for the poor, often by companies linked to government officials that have no building experience, residents in many cases have complained that their new homes are falling apart. In 2010, the government acknowledged that it would cost £150 million to demolish or rebuild collapsing houses built under the Reconstruction and Development Programme.
Crisis is particularly marked in education. Maths and science education for South African schoolchildren was last year rated in the Global Information Technology Report of the Geneva-based World Economic Forum as the second worst among 144 countries measured, ahead only of Yemen. This acute failure in education is lamented by the veteran liberal journalist Allister Sparks, former editor of the Rand Daily Mail, which was forced to close by the old apartheid regime after it exposed government corruption.
Sparks says many rural schools still take place under trees. In the towns and cities 3600 schools have no electricity and 2400 have no running water, while 92% of all schools have no library.
"We have one of the largest education budgets in the world, yet our performance is appalling," says Sparks. "Where is the money going? It all means that millions of unqualified, barely literate youngsters are being deposited on to the labour market. It happens every year. Moreover, it is a labour market in which the unskilled worker is becoming obsolete, in which the requirement is for ever-higher technical skills.
"After 20 years of freedom the ANC regime has failed to provide even the semblance of a decent education. Schoolchildren and teachers have been betrayed by greedy politicians and bureaucrats who have been too preoccupied with sating their own appetites and ambitions to provide an efficient, modern education system.
"Only 20% of black pupils pass national examinations. It is common for there to be 50 to 60 pupils per class in black areas."
He added: "I still seethe when I drive through rural areas and see children walking four to eight miles to school and back every day. It must be 10 years since I first wrote suggesting there be comprehensive school bus services in these areas to save them those hours that could be better spent studying. But if our government has one overriding talent, it is for doing nothing."
The ANC will nevertheless be returned to power this week and Zuma will continue as president. Despite a saga of cronyism and shamelessness dubbed by commentators as worse than the Watergate scandal that brought down US President Richard Nixon, the ANC has staying power that comes courtesy of its legacy of liberation and mass handouts of minimal social grants to the poor. Despite the barely tolerable unemployment levels, many members of the black majority see the ANC as the only party that might one day raise them out of dire poverty. The ANC is still in the genes of most of the people: it is still seen as the body that did most to end apartheid, and many black voters remain patient with it for that reason.
Cracks will show, however, following the poll. Some influential citizens, including Mandela's friend and fellow Nobel Peace Prize winner, Archbishop Desmond Tutu, have said that for the first time their vote will be withheld from the ANC this week.
In a withering attack, 81-year-old Tutu, below, said last week he was happy that Mandela had died - so that he does not have to see what Zuma and other ANC leaders are doing to the country. Confirming that he would not vote for the ANC, Tutu told a newspaper: "I didn't think there would be a disillusionment so soon. I'm glad that Madiba [Mandela's Xhosa clan name] is dead. I'm glad that he is no longer alive to see this.
"We dreamt about a society that would be compassionate, a society that really made people feel they mattered," Tutu, added: "You can't do that in a society where you have people who go to bed hungry, where many of our children still attend classes under trees."
Among many shack-dwellers in slums around cities such as Johannesburg and Cape Town, anger is intense. The biggest shack-dweller organisation, Abahlali baseMjondolo, issued a pre-election statement saying: "Twenty years after apartheid we live like pigs in the mud, our children die of diarrhoea, we are forced into transit camps at gun point, the police beat and shoot us in the streets ... We were promised jobs, but even a job picking rubbish needs an ANC membership card.
"We are lectured about our freedom by people who do not know what it is to make a child sleep with only water in their stomach and who have never been beaten by the police for expressing their views. As usual we are ordered to accompany politicians and businessmen to the stadiums to cheer our oppressors."
For the liberal middle class, both black and white, objections to Zuma include his historic escapes from prosecution for rape and his expenditure of £15 million of taxpayers' money to build a luxury home in a remote area of Zululand amidst a sea of rural poverty.
Zuma has been warning rural people at election rallies that voters who abandon the ANC will "attract the wrath of the ancestors." He also said: "The ANC will rule until Jesus returns." This time, again, the ANC will be returned to power, but political tectonic plates are moving. The writing is on the wall. It could just be the last time.
Fred Bridgland has been reporting from South Africa for 25 years. His latest book, a critical biography of Winnie Mandela, will be published this year.