Jacob Zuma danced and joked at his party in Johannesburg on Wednesday, but his 75th birthday was not a happy one. Tens of thousands of South Africans were protesting against the president again, days after crowds took to the streets in the biggest anti-government demonstrations since the end of apartheid. They were sparked by his sacking of the respected finance minister Pravin Gordhan, which prompted two agencies to downgrade the country’s international credit rating to “junk” status. But the crisis has been long in the making. The then ombudsman warned of “state capture” by business interests last year. Leading figures in Mr Zuma’s own party, the African National Congress, are increasingly public in their criticism, and anti-apartheid luminaries have condemned him. The other members of the tripartite alliance – the South African Communist party and Confederation of South African Trade Unions – sped his rise but have now urged him to go. A no-confidence vote in parliament is pending.

Mr Zuma, an anti-apartheid veteran, is a consummate survivor. The vote is unlikely to oust him, not least because he has built a patrimonial party packed with dependents. He is due to stand down as ANC leader in December (and president in 2019) and wants a friendly face, ideally his ex-wife Nkosazana Dlamini-Zuma, formerly chair of the African Union commission, to succeed him. Beside his legacy, he is no doubt contemplating the 700-plus corruption charges, dropped years ago, but since due for reinstatement, which still hang over his head. Opponents are backing his deputy Cyril Ramaphosa, who has become more openly critical but has disappointed supporters many times over the years. Other candidates may yet gain ground.

The real battle is not over this powerful and divisive personality, but the future of his party and his country. Few liberation organisations make a successful long-term transition to the utterly different business of government. The ANC has ruled unchallenged since the end of apartheid more than two decades ago, with impressive achievements, and the problems it faces are not solely of Mr Zuma’s making. Some think he is more symptom than cause.

Mr Zuma has shrilly and cynically blamed “white monopoly capitalism” for attempts to oust him. He blusters about a “radical economic transformation”, including dramatic action on land redistribution. These speak to real and important concerns, but in the crudest terms. South Africa’s stagnating economy has not delivered for too many citizens. Unemployment is up. Mr Zuma’s vaunted concern for the poorest would be more convincing if crony capitalism had not flourished on his watch, and if he had not spent huge sums of public money on home upgrades, including an amphitheatre.

The ANC must choose its future: to drift on as a clientelist party engaging in lowest common denominator politics while nourishing unhealthy relationships with tycoons; or it can embrace its moral heritage and democratic traditions with a fair and free selection process, choosing a leader who will strive to build a country that serves all its people. The ANC lost cities in last year’s local elections; its rural base is weakening. Yet the main question is whether its support will dip below 50% in 2019. So for the country and the party, the ANC must rise to the challenge.