What do the successful prosecutions of the yellow-jacketed Tony Yengeni and the wayward Winnie Madikizela-Mandela say? What about the pending corruption investigations into Deputy President Jacob Zuma, former transport minister Mac Maharaj and African National Congress hanger-on Schabir Shaik?

That we are a nation of corrupt retrogrades? Hardly. What it shows, most significantly, is that an independent prosecutorial authority, called the National Directorate of Public Prosecutions, is working and has become a cornerstone of this constitutional democracy.

That the office of incumbent Bulelani Ngcuka has so far been able to withstand pressure and conduct sensitive investigations into powerful individuals has earned it, and the country, the kind of credibility not enjoyed in many established democracies where the political and financial inner circles are often considered untouchable.

That a democracy so young can spawn institutions that do not distinguish between pauper and king is laudable. Nine years on, we find these institutions being put to the test.

The controversy surrounding the Scorpions investigation into Zuma is proving a litmus test of whether our society can withstand rigorous interrogation of its leaders by the very institutions they created. Since it became public that Zuma is being investigated for allegedly soliciting a bribe from a French company involved in the multibillion-rand arms deal, there has been much tension in the ranks of the ANC and the government.

There have been behind the scenes whispers about Ngcuka's real intentions for investigating Zuma. Suggestions have been made by some ANC leaders, including Zuma, that the investigation formed part of political machinations presumably surrounding the low- intensity presidential succession battle already raging in ANC ranks.

All these were worrying but harmless accusations because the office is protected by the Constitution, by legislation and by the commitment of South Africans to clean governance and the creation of a decent society.

It is the more sinister whispering campaign that should provide cause for concern. For some time now there have been attempts to plant stories in the media about Ngcuka's private life, culminating in this week's dissemination of an e-mail containing a slew of accusations against him by unnamed individuals.

If there is an iota of truth in the allegations against Ngcuka, then surely it is incumbent upon the good citizens who have access to this information to bring it before the country's many investigative agencies. For he, just as the people he investigates, is not above the law. It is the integrity of his office, not the incumbent, that must be protected from slander and innuendo.

What is important at this juncture is that we do not allow our institutions of governance to be compromised. Chief among those is the Office of the Deputy President, which has got to be above reproach, its integrity protected at all costs. Whether Zuma is guilty of the crimes levelled against him is something that the courts, guided by the country's premier investigative organisation, will determine. That process must be given a chance to run its course. It is vital that investigations into Zuma and other prominent individuals be allowed to continue without any covert or overt pressure.

With acknowledgements to the Mail & Guardian.