President Jacob Zuma. Photo: Leon Nicholas.

The African National Congress’s succession dogfight has become the most reliable filter through which to assess both President Jacob Zuma’s administration and the ruling party. Constant bickering appears to weaken Zuma as South African president, as he has had to adopt an almost permanently defensive stance inside the ANC.

How has this happened? And why has the coalition of factions that deposed Thabo Mbeki, headed by a president who stood triumphantly astride the party only two years ago at the 2010 national general council (NGC), weakened so quickly?

In part the answer lies in a development that predates Zuma. In reality, patronage rather than ideology is now the key driver of internal politics inside today’s ANC.

The succession cannot be assessed from the perspective of traditional left-right tensions. In the broad coalition ranged against Mbeki in 2007, it was still possible to discern some ideological coherence.

This may have been due to the fact that for a decade their common nemesis imposed a right-leaning policy hegemony on the ANC, and even the patronage networks supported by Mbeki’s ANC reflected this ideological bent. Coherence in the anti-Mbeki alliance was therefore an outcome of the ideological nature of exclusion during Mbeki’s decade of power.

Patronage under Zuma has no such parameters. The absence of ideological boundaries accounts for the fluidity of the actors and the arbitrariness of the issues in dispute during recent succession-linked public squabbles that have brought the Polokwane alliance to its knees.

Cosatu – or sections of it supportive of general secretary Zwelinzima Vavi – have made Zuma-linked corruption their rallying cry. The ANC Youth League has found its hitherto misplaced Marxist textbooks, becoming the new standard-bearers for nationalisation and uncompensated land expropriation.

In this they have curiously found no allies in the SACP, which for its part has uncomfortably found itself perceived as siding with Zuma and some increasingly unpopular financial underwriters.

In the ANC this reality is underlined by the fact that leadership contests are almost always about a set of interests rather than just the fortunes of an individual leader. This brings me to the big question, which is whether or not there will indeed be an actual contest for the presidency of the ANC when the party’s elective conference rolls round in December.

Depending on who one speaks to, Deputy President Kgalema Motlanthe is either totally against contesting Zuma for the ruling party’s presidency, or quietly biding his time to make his move. Nominations for the elective conference will start in October.

Until then, it is safe to say that much of what is being said in his name has more to do with the ambitions of senior ANC figures who are against the incumbent and less to do with Motlanthe’s own decisions about his political future.

Motlanthe, a seasoned politician, is keeping his powder dry for many reasons. Unlike the ANCYL (the main cheerleaders of the anti-Zuma campaign) and other pretenders to the throne, Motlanthe knows very well that going for Zuma publicly is one thing; galvanising the machine in the ANC to oust him after just one term is another.

Contesting Zuma in the ANC also raises the stakes considerably. If Motlanthe does decide to run against Zuma, he runs the risk of playing an all or nothing game that could set in motion a process that would see him lose the position of Deputy President of SA if his bid for power goes south in Mangaung in December.

Neither Zuma nor his backers will be happy with a deputy in the state who has launched a takeover bid in the party. And Zuma would presumably have to reward his new ANC deputy by handing him the state post in 2014. The reverse is also true. In the event Motlanthe successfully contested the ANC presidency, there would be very few among his crowd who would be agreeable to keeping Zuma on in the Union Buildings, even before 2014.

The removal of Mbeki in 2008 has in a sense created a precedent for a zero tolerance approach to two centres of power.

While those who want Motlanthe to contest Zuma are planting carefully choreographed stories about his ”readiness” to go toe to toe with Zuma, the reality is that Motlanthe is weighing his options carefully, watching the powerful provincial elites in the party, inextricably tied to economic interests in their localities, some of whom are rallying behind him to take on Zuma.

Moreover Motlanthe will also have to internalise the ugly reality that it is likely that whoever replaces Zuma – either in 2012 or 2017 – will face the same perpetual succession dogfights, driven by the same relentless hunger for state-led largesse.

Perhaps most important, opposition to Zuma has not consolidated into a coherent faction, and comprises a swirling, confused and frequently realigning mess, still without an agreed champion.

The “anyone-but-Zuma” approach of Human Settlements Minister Tokyo Sexwale underlines this inability of the anti-Zuma camp to cohere ideologically on the one hand, and their failure to rally around an agreed slate around which lobbying can take place within the provinces.

At present any effort to unseat Zuma will have to take into account Zuma’s strength in the ANC, even if this is contested. Despite the division, Zuma has secured the numerical edge. In the biggest province (KZN) he is in pole position.

Even in contested provinces such as the Eastern Cape, Gauteng and Limpopo, he has a sizable chunk of the vote. In the Free State and Mpumalanga, he is the candidate of choice. Smaller provinces such as Northern Cape, Western Cape and North West will also be split.

While Motlanthe’s acolytes may believe contesting Zuma is doable, the deputy president is wise enough to know that gambling his political future and fortune on anything less than guaranteed victory is not only foolhardy, but could end his illustrious career in the party and the state.

And virtually none of the actors who would have him front their interests and take Zuma head on can give him a guarantee of victory.

- Brown is CNBC Africa anchor for Political Exchange, a current affairs show focusing on African political economy.