The supporters of Jacob Zuma, the leader of South Africa's ruling African National Congress party, had promised to bring the city of Pietermaritzburg to a halt yesterday when their hero appeared at a hearing into corruption charges levelled against him by state prosecutors. In the end they produced crowds of only a few hundred.

That was not really a comment on the man himself, who remains popular, not just among his own Zulu tribe, but in the esteem of South Africa's dispossessed, whose cause he has consistently championed. Rather, it was a reflection of the occasion: a sober judicial hearing into the question of whether the ANC leader should face a full trial on corruption charges related to the 1999 $4.8bn deal to modernise South Africa's armed services, when Mr Zuma was the country's vice-president. Mr Zuma's close associate, Schabir Shaik, has already been found guilty of corruption in seeking bribes in his boss's name. But Mr Zuma himself has denied all involvement, declaring that the charges have been trumped up by his opponents for political reasons.

The politics are certainly fraught. The ruling ANC has been bitterly divided since President Thabo Mbeki's 2005 decision to fire his deputy in the wake of Shaik's imprisonment. But Mr Zuma came back strongly in the ANC's leadership elections last year. He is now likely to become president when national elections are held next year. This explains Mr Zuma's determination to get the trial stopped in its tracks now. It also explains the anger of his supporters who smell a political plot in all this.

They may not be wrong. Mr Zuma is certainly a contentious figure, but he is also a formidable politician with a popular appeal matched by no other ANC member. He has also proved far more robust than President Mbeki over Robert Mugabe's strangulation of Zimbabwe. It would be a tragedy for South African politics if this potential president were removed by trumped-up charges. But then it would a wrong, too, if the functioning of the law was impeded in the interests of politics.

Africa needs clean government. If the courts decide, on their own grounds, not to proceed, it would be a happy conclusion. But if a trial is needed to affirm the innocence or otherwise of the ANC's chief, then let it proceed.