This is evidenced in the stinging rebuke by Bulelani Ngcuka, the former national director of Public Prosecutions, published at the weekend as an open letter.

And, as former president Thabo Mbeki did last week, Ngcuka challenges Heath to provide evidence to justify his claims that they essentially used state resources to engineer charges against Zuma.

As in many other instances when the president defied conventional wisdom and propriety, Heath appears necessary for Zuma in his battle to be re-elected ANC president.

But what does the good advocate have to offer Zuma that makes it so important for Heath to be part of a government structure - one incredibly important in the fight against corruption - rather than the backroom adviser he has been throughout the president's rape and corruption trials?

This, unfortunately, has not been made quite clear, particularly in the context of the quality of the work done by Heath's predecessor.

How does one justify moving aside Willie Hofmeyr, who has played a pivotal role in combating crime in South Africa - both as head of the Asset Forfeiture Unit and more recently the SIU - for a senior citizen who had pinned his colours so firmly to the Zuma mast?

Of all the puzzling appointments Zuma has made, returning Heath to the SIU must count as one of the most controversial and contested.

Unfortunately, it is quite conceivable that Heath might survive calls for his resignation because Zuma wants him around. We might not be sure why, but we can speculate that it is important for the president to have men in his corner to rely on in troubled times.