The formation model of collegially shared power (CSP) through the emergence of internal political forces parity in the conditions of common external geopolitical threats is tested on the material of Southern African countries in the 2nd half of the 20th century. The approach itself is based on the ‘geopolitical theory of collegial power’ by the American sociologist R. Collins, which describes the processes of formation of new political systems with ‘checks and balances’ through the centralization of military coalitions. A qualitative comparative analysis (QCA) of decolonization cases in Botswana, Namibia, South Africa, Zimbabwe, Lesotho and Swaziland is conducted on 4 dependent variables: presence/absence of coalition governments, intra-elite repression, government accountability to parliament and the right of the head of state to appoint members of parliament. Decolonization is interpreted as a transition to ‘black majority rule’ in which the population of a country has the ability, at least nominally, to approve and remove governments through general elections. The results of the analysis show that the previously derived model does not fully describe the cases under study, but, with the exception of the Botswana case, the emergence of domestic political forces parity during decolonization does correlate with high levels of CSP. It also reveals that the theory of CSP should take into account the experience of political systems with a dominant party. It is concluded that the analysis of the new sampling allowed both to partially confirm the results obtained earlier and to reveal certain limitations of the ‘geopolitical theory of collegial power’.