For those of us who simply don't buy acting National Prosecuting Authority director Mokotedi Mpshe's story about why he dropped the fraud, corruption, money-laundering and racketeering charges against Jacob Zuma this week, I thought it might be worth considering five more plausible explanations.

Personal Betrayal and Revenge. An astounding piece of information revealed by Mpshe in his announcement this week was that the foot soldiers of the apparent crude conspiracy against Zuma (I'll call them Buls and Leo) deliberately acted when Mokotedi was on leave. In other words, they shafted their boss.

In fact, Mpshe has been made to seem like a blithering idiot, since it was he who claimed when the charges were reinstated at the time of the ANC's Polokwane Conference that no political meddling had taken place. Hence Mpshe has every reason to take Buls' and Leo's actions personally. A natural reaction would be for Mpshe to turn around and say to them: "You may have found it funny to f**k me up and to f**k Zuma up - but see who gets the last laugh in all this. I plan to f**k up the entire country by letting Zuma off the hook."

Personal Ambition. Imagine applying for the job of NPA director (a position ultimately appointed by the president) and writing on your CV: "During 2008 and 2009 I actively led an unsuccessful attempt to prosecute you on fraud and corruption charges".

Not the best recommendation for the job. In fact, leading an unsuccessful attempt to prosecute or impeach a president is a ticket to total obscurity, as discovered by Kenneth Starr, the special prosecutor who tried to impeach Bill Clinton when the former US president falsely denied having being sexually serviced by Monica Lewinsky.

Mpshe's rhetorical response during this week's press conference, when Ben Said of e.tv boldly questioned whether Mpshe might not resign over the whole affair, was: "Who would not want to keep their job in the present economic climate?"

Assuming that Mpshe not only wants a job, but that he quite fancies being the permanent head of the NPA or some similar national body, dropping the charges against his future boss was a smart career move.

Political Pressure. ANC heavyweights have for some months warned that prosecuting JZ (aka JC) might lead to destabilisation of the country. Roughly translated that means: "You touch JZ, we f**k up the country". Or put another way: "You take away our prophet, expect divine (and more worldly) retribution". Mpshe may have felt a little uneasy about being compared to the Roman heathens who crucified an earlier messiah.

Covering up for Mbeki. Although Mpshe appears to have been bold in revealing the grimy details of the Leo and Buls phone conversations, Mpshe pulled off a spectacular acrobatic feat on the high-wire, by consistently denying any evidence implicating Thabo Mbeki himself.

Again it was Ben Said of e.tv who was somewhat incredulous: "But Leo and Buls said that they consulted the Big Man in Shell House".

To which Mpshe replied: "Yes, but I don't know who they meant by the Big Man". Fair enough - after all the previous "Top Man" in Luthuli House was actually not very big.

What's more, Mpshe went on, I can't be sure that just because they claimed to have met the Big Man to organise a comeback strategy for him, that they really had met him. Well done Mpshe - you managed to expose the foot soldiers and shield the Top Man (something you might not have managed to do if the full audio tapes had made it into court).

Protecting the Revolution. Bear with me for a moment, because this is the most contorted explanation for wanting to let Zuma off the hook. However, it may be the line of argument privately supported by many progressive and intelligent cadres in the ANC, including ministers and NEC members.

If you believed Mbeki had led the "1996 class project" in the ANC, which was turning SA into a uncaring free market society, in which black capitalists could compete more equally with their white counterparts to exploit the black masses - but in which the masses derive little benefit - then you would have been looking for a new champion for working class policies in the ANC.

As Mbeki's most prominent opponent (and the opponent with so little to lose and so much to gain), Zuma represented an opportunity to turn the ANC around and to reinstate a left-leaning version of the National Democratic Revolution as set out in the RDP back in 1994.

In this case, the fact that JZ's palms were greased to the tune of a few million bucks by low-lifes from the arms-dealing world is no more than an annoying distraction from the goal of reinstating the ANC as a vehicle for real social transformation. After all, everyone was feeding at the same trough, including Mbeki nogal.

So a Zuma presidency represents much more than the ascent of his own grubby self into the Union Buildings - it represents the only hope of social transformation in the country.

Incidentally this is the only reason for releasing Zuma for which I personally have some sympathy (although I doubt that JZ will deliver on his promises to the left). I also suspect that this reason for overlooking Zuma's flaws is privately supported by many upstanding and intelligent cadres in the leadership of the ANC, who constantly tell us that there's no case against Zuma, while knowing that the case against him is very strong.

It's certainly the view of people on the left of the alliance like Vavi and Blade. So, well done Mpshe, you may have slammed the door on Mbeki's class project.

In any case, whatever your reasons Mr Mpshe, I feel you have sentenced SA to stormy weather and clouds for years to come. You chose to keep your job and let Msholozi off the hook. I think we'd probably enjoy a little more sunshine over the coming months and years if you'd done the right thing - resigned yourself and let Zuma have his day in court.

Ben Cashdan is a filmmaker and political commentator.

With acknowledgements to Ben Cashdan and The Star.