JOHANNESBURG — Nelson Mandela’s African National Congress once inspired hope across Africa. It helped liberate black South Africans from white-minority rule, promoting reconciliation with former oppressors and the ideal of a postracial “Rainbow Nation.’’

It even seemed poised to lift up the rest of the continent with its vision of an African renaissance.

But as ANC members gathered Saturday to begin electing a new leader, many analysts described the still-dominant party as a shadow of what it once represented — bereft of ideals, roiled by insiders fighting over diminishing spoils, abandoned by a growing list of disillusioned graying party heroes known as “stalwarts.’’

For many at home and across Africa, the once heroic liberation movement is now synonymous with corruption and cynicism. South Africa has become a normal nation.

The new leader is to be announced Sunday. The winner of the party vote is expected to become South Africa’s next president in the 2019 elections unless the ANC loses its overwhelming strength in Parliament, which selects the nation’s top executive.

Its present leader is President Jacob Zuma, who as South Africa’s head of state since 2009 has been at the center of a series of personal and political scandals. He will step down as head of the party after his successor is chosen, possibly as early as Sunday, at an elective conference in Johannesburg, the nation’s largest city.

Two front-runners are locked in a tight race to succeed him, embodying starkly different strains within a deeply divided party.

Nkosazana Dlamini-Zuma, a medical doctor and antiapartheid veteran who served in several roles in previous governments, is also a former wife of Zuma. She has his support and that of many of his allies and has adopted his populist rhetoric.

Cyril Ramaphosa, the deputy president, has won the support of some of Jacob Zuma’s fiercest opponents: business groups and middle-class black voters in cities.

His own record in business, however — as a former trade union leader whose ANC connections helped him become one of the country’s richest men — has made him a representative of the gulf between South Africa’s tiny new black elite and its poor.

Critics have focused on Jacob Zuma, 75, to explain the ANC’s precipitous decline. And Zuma, who has six wives and as deputy president was tried and acquitted on a rape accusation, makes an easy target.

But the problems go beyond just one man. Like other liberation parties in southern Africa, including those in Zimbabwe, Angola, Namibia, and Mozambique, the ANC has never lost power since ousting white rulers and has come to focus on retaining that power and the access it provides.

In South Africa — where the economy has stagnated under Zuma — patronage and corruption have built a system that will be difficult to dismantle. In many of the ANC’s rural strongholds, the party remains the main source of business and jobs.

Nationwide, access to state enterprises has been the reward for Zuma’s allies, including friends with few professional skills and the Guptas, a wealthy family who have acquired widespread business interests.

State enterprises, through the awarding of contracts, or tenders, have created an entire class of ANC loyalists sometimes derided as “tenderpreneurs.’’

“There is nothing exceptional in what has happened to the ANC because it is the path that all African liberation parties have taken,’’ said Ralph Mathekga, a political analyst. “It has failed to modernize from liberation politics to managing a complex modern society.’’

“People personalize it to say it’s all about Zuma, but every post-liberation African society risks having a Mobutu,’’ he said, referring to Mobutu Sese Seko, the notoriously corrupt former ruler of Zaire, now the Democratic Republic of Congo.

“What makes this different is that people’s expectations of the ANC were higher because it was a latecomer and because of Mandela.’’

Apartheid ended in 1994, well after liberation had swept the rest of the continent. Mandela served as South Africa’s first democratic president from 1994 to 1999. His successor, Thabo Mbeki was forced out of power in 2008 before the end of his second term by Zuma and his allies.