Over the past eight years President Thabo Mbeki has endorsed Zanu-PF's victories in a string of stolen elections, opposed the imposition of any sanctions on the regime in Zimbabwe, acted to shore up Robert Mugabe's support within SADC, and successfully diverted international outrage into various meandering and ultimately futile diplomatic initiatives. The only surprise about his obdurate refusal to do or say anything constructive about the latest crisis is - as Tony Leon noted in Business Day recently - that "we are at all surprised."

Still, the extremes to which Mbeki has - apparently - been willing to go in support of Mugabe still has a residual capacity to shock. On Friday the Mail & Guardian confirmed that Mbeki had both known about and condoned the transhipment across South African territory of the Chinese weapons, intended for the Zimbabwean military, aboard the An Yue Jiang. Indeed, the newspaper reported that according to its sources Mbeki had given a "direct order" to the ministry of defence and national conventional arms control committee that the weapons be waved through.

This revelation seems to contradict Mbeki's statement to journalists in New York on April 16 that "those weapons would have had nothing to do with South Africa. I really don't know what Zimbabwe imports from China or what China imports from Zimbabwe." The fact that cabinet clearly knew about the arms from early on also casts doubt on Aziz Pahad's denial of any knowledge of the shipment. The deputy minister of foreign affairs told journalists on April 17 "We are not able to determine as Foreign Affairs what are the goods that are going from one country to another. We are not aware of any nature of the consignment because we don't have the capacity to go and check on any consignments on any ship coming into South Africa."

Over the past month numerous formerly supportive politicians, commentators, and diplomats have pealed away from Mbeki on the Zimbabwe issue. Indeed, according to the Mail & Guardian, his insistence on letting the weapons through has alienated some of his closest allies in government. "Everyone is asking what has happened to him," it quotes one person as saying. "It is very hard to explain."

If there is now a consensus that Mbeki supports Mugabe - and has done since 2000 - there is a lot less certainty about why this is the case. The destruction of the Zimbabwean polity and economy was never in South Africa's national interest. It has done no good for Mbeki's international reputation. And it wasn't obviously in his political self-interest either - it was one of the contributing factors to his downfall at Polokwane. Between 2000 and 2003 Mbeki argued that effecting a final solution to the "legacy of colonialism" was the overriding priority in Zimbabwe. But the great majority of white farmers were forced off their land years ago - and so that consideration can hardly still apply.

Mark Gevisser, has ascribed Mbeki's approach towards Mugabe to a combination of "filial obligation", "diplomatic strategy," stubbornness, and a belief that Zanu-PF would never concede power anyway. Professor Stephen Chan makes similar claims. He has argued there are five reasons for Mbeki's "extraordinary patience" towards Mugabe: 1.) Mbeki knows that Mugabe is backed up by "his hardline generals" - people who will not just disappear at his say so; 2.) He does not see Tsvangirai as a "viable alternative president". 3.) Mbeki and Mugabe "simply get on intellectually" 4.) Mugabe holds Mbeki in "thrall" as the "grand old man of liberation"; 5.) Mbeki "has blind spots" and is stubborn.

When one measures these putative reasons against the thing they have to explain they do come across as faintly inadequate. Like darts thrown against an elephant they can't but hit the target. Still, they fail to penetrate very deeply. What man would stand back and allow the utter immiseration of a country just because he views its despotic leader as a kind of dad? Or, because he regards the head of the main opposition party as beneath him intellectually?

A more substantive explanation has recently been provided by two observers on opposite sides of the ideological spectrum. In an essay on the Zimbabwe crisis in the latest edition of the London Review of Books R.W. Johnson argues that "Mbeki's fundamental position was that, as a fellow national liberation movement (NLM), Mugabe's ruling Zanu-PF had to be maintained in power at all costs." This is a view shared by the SACP's Jeremy Cronin. In a speech last week he said he personally believed "that what informs much of President Mbeki's Zimbabwean strategy is the belief that national liberation movements in our region should close ranks. This is informed by a conviction that the crisis in Zimbabwe is being used as an entry point by imperialist powers to reassert hegemony over a former colony and eventually over our whole region."

Still, one wonders whether this explanation can bear the entire weight of that which it seeks to explain. The bulk of the ANC leadership - including Jacob Zuma and Kgalema Motlanthe - once went along with this line of thinking. But they seem to have now realised that, beyond a certain point, it becomes barbarous to persist with this course of action.

Once it became clear that the presidential and parliamentary polls had been lost to Zanu-PF, Mbeki had a great deal to gain from ensuring Mugabe's peaceful exit from power. His decision to back Mugabe from 2000 onwards had had disastrous consequences for the region. But the MDC's win provided him with an out. His spin doctors were already spreading the message that "quiet diplomacy" was on the verge of vindication. But he humiliated them and himself by standing by Mugabe after the old tyrant decided to stay on. His stance has left him isolated both at home and abroad. The only obvious beneficiary has been ANC President Jacob Zuma, who has been made to look positively statesmanlike by comparison.

There are other curiousities about Mbeki's relationship with Mugabe. The cover of a recent issue of the British magazine Private Eye has a picture of Robert Mugabe and Mbeki under the heading "Zimbabwe crisis talks". Mugabe says to Mbeki "I'll resign if I can keep my job." To which a smiling Mbeki replies, "Anything you say boss." Gevisser observed in his article that on Mbeki's recent visit to Harare, "Fondly clasping Mugabe's hand, he averred that there was ‘no crisis' in Zimbabwe. The smirk on the father's face left no doubt about where the power in this relationship lay." In a column a couple of weeks ago Justice Malala derisively described Mbeki as Mugabe's "foreign minister."

All three comments point at the same thing: despite his obvious vulnerability it is Mugabe who holds the whip hand in their relationship. If one did not know otherwise one would almost think - as Malala's ‘foreign minister' jibe suggests - that it is Mugabe, not the South African taxpayer, who pays Mbeki's salary at the end of every month.

So, the honest answer then to the question of why Mbeki has backed Mugabe is that I just don't know. I get the sense that there is something else - some strange and secret bond - that binds Mbeki and Mugabe together. I would almost class this thing as a "known unknown." It is there and if we only knew what it was a great deal of what currently appears inexplicable would suddenly make sense.