The party will for the first time face the people shorn of its moral shield, Mandela, who, as US President Barack Obama observed, now "belongs to the ages".
Without its father's protection, the ANC will be subjected to internal and external scrutiny on a scale unprecedented since Mandela made his walk to freedom from life imprisonment on February 11, 1990.
The current picture is not pretty. South Africa under President Jacob Zuma is facing crises on multiple fronts - Zuma's personal corruption; the spread of graft to the head of state's top ANC colleagues in government; threats to press freedom and to the judiciary; massive unemployment, including a staggering 70% rate among men under 35; erosion of education and health systems; and a blazing and dangerous conflict in the wake of last year's Marikana massacre, in which 34 striking miners were gunned down and killed by police.
Marikana is a flash point that is being likened to the Sharpeville massacre of March 21, 1960, when the apartheid-era police force shot dead 69 men, women and children among the demonstrators protesting against the country's notorious race-based laws.
In a response that has caused huge anger among miners and widespread shock elsewhere, the ANC government reacted to the Marikana killings by, improbably, charging the miners - who were battling for wage and living condition improvements - with the murder of their colleagues.
The ANC's handling of the strike and its aftermath, coupled with allegations of cronyism and venality among its top leaders, has led to widespread unhappiness, and a raft of new political parties is riding the wave of disenchantment. Unprecedented questions are being raised about whether the ANC of Jacob Zuma can hope to retain power in the 2014 poll. Latest opinion polls suggest that the party's share of the popular vote will fall from 66% at the last election in 2009 to 56% at most next year. For a party that prides itself on having brought freedom to the black majority, this would be a symbolic blow.
"The ANC no longer has leaders," said Justice Malala, one of South Africa's most respected political commentators and newspaper columnists, in a ferocious attack. "It has zombies who mindlessly follow this one leader and do his bidding. The ANC is compromised. It has lost its moral compass and its leadership of society.
"We will remember the reign of Zuma not for its achievements but for the cowardice, callowness and bankruptcy of the leadership that he brought with him. We will remember his lackeys for their bowing and scraping and their destruction of the continent's greatest liberation movement. What an ignominious end for the party of Mandela."
Different critics focus on their favourite concerns about the modern ANC. Malala's particular bugbear is the so-called "Nkandla Scandal", involving the spending of the equivalent of £15 million of taxpayers' money to enhance Zuma's luxury private home in rural Zululand. A so far secret report - expected to be damning - by Thuli Madonsela, the public protector, or anti-corruption watchdog, is forecast to be ready for release by mid-January.
When South African newspapers published photos of Zuma's James Bond-style retreat, the government warned editors that they faced arrest for breaking security laws. One newspaper responded with the headline "So, arrest us" above yet another photo of the house. There has been no action so far against the papers. They are also hugely concerned about a controversial media bill that has been approved by the lower house of parliament and awaits endorsement by the upper house.
Nobel Prize-winning author Nadine Gordimer, Mandela's next-door neighbour in Johannesburg until his death last Thursday, has condemned the bill, calling it a threat to freedom in South Africa and comparing it to apartheid-era laws.
"The right to know must continue to accompany the right to vote," said Gordimer, a long-time ANC supporter. "The Protection of State Information Bill is not only flawed, it is insulting to all South Africans to be asked to stomach legislation that could be used to outlaw investigative journalism; and that makes the state answerable only to the state."
Gordimer said Mandela was opposed to the proposed legislation. She added: "People died in the freedom struggle, and to think that having gained freedom at such a cost it is now indeed threatened again. We got rid of apartheid but now we are going back to many of the laws that apartheid instituted in order to stop thought."
The dangers to the justice system under Zuma are of high concern to Dr Mamphela Ramphele, partner of the late Black Consciousness leader Steve Biko, who was murdered by apartheid policemen in 1977, and the mother of his two children. Ramphele, a former managing director of the World Bank, is the leader of a new political party, Agang ("Build"), formed in order to challenge the ANC. She argues that her country has lost the respect it enjoyed when the transition to an all-race democracy was completed in 1994.
She said: "Our president [Zuma] has manipulated the justice system to avoid charges of corruption [in connection with South Africa's 1999 £3.5 billion arms deal with European manufacturers]. He is fighting every step of the way to avoid surrendering for public scrutiny the documents upon which prosecutors based their decision to withdraw charges against him four years ago."
Veteran South African liberal journalist Allister Sparks, who spent decades writing in support of black majority rule, despairs about sky-high youth unemployment levels and the collapse of his country's education and health systems.
He wrote recently: "After 20 years of freedom, the ANC regime has failed to provide even the semblance of a decent education." He said schoolchildren and their teachers had 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".
The Mail & Guardian newspaper, which was in the forefront of the media struggle against apartheid, warned that the ANC government's indifference to the Marikana killings has changed families and communities across the land. The massacre has certainly changed how they see their relationship with their democratically elected government.
Marikana families feel abandoned by the ANC administration, the Mail & Guardian said, adding: "Our world can never be the same. What happened at Marikana was a deep echo from our apartheid past. It was unrestrained and brutal. It was also state-administered."
Sparks has been forecasting for the past two years that the ANC will fragment into different ideological components, saying: "It will take place incrementally, triggered by catalytic events that will occur at unpredictable intervals."
Marikana followed by Nelson Mandela's death could add up to that catalyst. The future now of the Rainbow Nation has never looked more uncertain and unpredictable than at any time since the black township uprisings of the 1980s that provoked a five-year state of emergency.
l You can read a longer version of this article at www.heraldscotland.com