Three developments in the past week point to a realignment of political forces in post-apartheid South Africa, one that may result in the ruling African National Congress (ANC) losing support on two fronts.

The trio of events are, firstly, the victories by the Democratic Alliance (DA) over the ANC in municipal by-elections in the Western Cape, secondly, the divisive and vicious leadership struggle in the Congress of the People (Cope), and, thirdly, the attempt by elements in the ANC to initiate disciplinary charges against Zwelinzima Vavi, the general secretary of the Congress of South African Trade Unions (Cosatu) .

The DA's triumph in two Western Cape by-elections is significant because the two wards were considered as ANC strongholds, in part because they were won decisively by the ANC in the 2006 local government elections.

In the Heideveld-Gugulethu ward the DA won 60.3 % of the votes as against its meagre 26.2 % in 2006, while the ANC netted 37.7 % of the votes cast against its 53% in 2006. Thus, while support for the DA increased, the ANC shed a conspicuous proportion of its 2006 vote.

A similar trend was reflected in Grabouw. The DA share of poll was 48.1 %, a nearly fivefold improvement on the 9.6 % that it recorded in 2006. The ANC attracted 44. 8 % of the votes cast, which represented a 26% decrease in its share of the poll since 2006.

Zille considers the Grabouw result more important as a pointer to the future than that at Heideveld-Gugulethu. The reason is simple: a majority of voters in Grabouw are black indigenes. To quote Zille: "The DA has over the past four years established a very strong voter base in coloured communities, as the Heideveld-Gugulethu result re-confirmed. But significant progress among black voters eluded us until the breakthrough at Grabouw."

Politically-speaking the situation in the Western Cape is sui generis for two reasons. It is the only province in South Africa in which provincial governance is not exercised by the ANC, the DA having ousted the ANC provincial government in last year's election. It is furthermore the only province in which the indigenous blacks are not in the majority. According to the latest survey of South Africa by the Institute of Race Relations coloured people out number their black compatriots by more than 2-to-1.

To make these observations is not to completely negate the relevance of the DA by-election victories in the Western Cape for the rest of South Africa, but, rather, to caution against the facile assumption that it is necessarily the harbinger of similar electoral triumphs elsewhere.

It might be noted that ANC activists, however, signalled their concern about the determination of the DA to garner greater support from the black community by attempting to disrupt DA political meetings leading up to the latest round of by-elections. Zille describes these disruptive ANC forays as an ominous foretaste of what might occur in the future if the ANC ever face possible defeat in a national election.

The leadership contest in Cope between Mosiuoa Lekota and Mhazima Shilowa, both of whom held high positions in the ANC during the presidency of Thabo Mbeki, is important because it seems set to split the party into two warring factions, each of which describing itself as the genuine Cope and castigating its rival as an impostor.

The impending schism is almost certainly  to lead to what might be termed as a division of the spoils: a scramble by the factions to appropriate party assets, occupy the 30seats won by Cope in last's April 27 election, and to the secure the allegiance of the 1.3 million citizens who voted for Cope in the  2009 election.

Of these "spoils" the most important in the long run is the loyal of the South Africans who voted for for the party, particularly if Cope implodes, an outcome that may have become probable, if not inevitable, since the decision of Mvuma Dandala, Cope's parliamentary leader and presidential candidate in 2009.

The main contenders for the 1.3-million votes are the ANC and the DA: the ANC because many of them are former ANC supporters if not members; the DA because it is the strongest of the parliamentary opposition parties and the only parliamentary party to have increased its share of the vote in the four national and provincial elections in post-apartheid South Africa.

The DA may have another advantage over the ANC: many Cope supporters were appalled by precipitous manner in which the Zuma-led ANC recalled Mbeki from his national presidential office hardly more than six months before his second and final term of office was scheduled to end.

The wounds of what Afrikaners refer to a broedertwis have not yet healed and the DA may prove to be the major beneficiary of the still smouldering resentment in the ranks of those who voted for Cope.

The third development pointing to a possible fundamental political realignment relates to preliminary moves by the ANC to haul Zwelinzima Vavi, the general secretary of Cosatu, before an ANC disciplinary hearing for publicly voicing his concern about corruption in the upper echelons of the ANC, the cabinet not excluded.

Vavi, who has confirmed that there is a move to indict him in his capacity as an ANC member, has described the move as unprecedented in the history of the tripartite alliance between the ANC, Cosatu and the South African Communist Party, (SACP).  It is more than that. It is a threat to the notion of dual and/or triple membership by cadres of the tripartite alliance, on which the alliance is based.

The problem is confounded by another factor.

The concern expressed about alleged corruption in the upper ranks of the ANC - and President Jacob Zuma's apparent insouciance about the allegations - were "not just the personal views of the general secretary." They were, to quote Vavi "contained in an official statement issued by the federation after its recent general executive committee meeting."

Cosatu's defence of Vavi was reinforced by statements from his affiliated unions. Thus, to mention one example, the National Education, Health and Allied Workers' Union described the threat to summon Vavi to an ANC disciplinary hearing as the "emergence of a fascist and dictatorial tendency" in the ANC.

While the ANC may not act on the threat to discipline Vavi, the possibility of which was discussed at an ANC national working committee meeting, there is little doubt that Cosatu is increasingly disillusion with Zuma's performance as South Africa's president. For that reason Cosatu may not support his re-election as ANC president at the ANC's elective conference in 2012.

If that happens, the conservatives in the ANC's leadership ranks may well intensify their support of him, the result of which will be heighten tensions in the ANC and an increase in the divisive forces within the organisation.

Tension between militant leftists in Cosatu (Vavi is a member of the SAC as well as the ANC) and a faction in the ANC, which is intent of preventing what it sees as an on-going campaign by Cosatu and the SACP to pressurise the ANC into adopting a socialist orientated agenda, is likely to continue for the foreseeable future.

If these centrifugal forces are unchecked they will either reduce the ANC to a dysfunctional political movement or the withdrawal of either the doctrinaire leftists or the hard line nationalists.

In that context it is interesting to recall that in the late 1990s Cosatu foresaw the possibility of having to withdraw from the tripartite alliance to establish a workers' party dedicated to the advance of socialism, a term that has been increasing used as a euphemism for communism since the collapse of the Soviet Union and its satellites in Eastern Europe.

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