Explaining Party Switching in an Institutionalised Party System: The Case of South Africa

Institutionalised party systems are said to foster stronger party allegiances and fewer switches. However, this expectation is called into question when we observe the case of South Africa. Despite being characterised by a highly institutionalised dominant party system as well as party-centred electoral and candidate selection rules, South Africa has experienced frequent episodes of floor-crossing over time. This article advances an analytical framework that links elites’ vote-seeking and office-seeking incentives to party switching and party system functioning. It posits that as elites strive for (re)selection and (re-)election, they will depart from smaller to larger parties, and this ultimately reinforces the party system of the day. Utilising an original dataset of 5,230 candidates to the National Assembly and the provincial legislatures of South Africa between 1999 and 2019, the study charts the overall rate of party switching and tests hypotheses postulating the effect of party size and candidates’ electoral marginality on the likelihood of switching parties. The analyses reveal that candidates from smaller parties and those who failed to be (re-)elected by the narrowest margin are more likely to switch parties in the next election. Additionally, most candidates who switched parties tended to move to parties that fared better than their original party in the next election; and they switched from parties that either did worse or stayed the same. But we did not find a strong correlation linking party performance to switches. The study highlights the role of intra-party competition in patterns of elite migration and reveals the importance of linking elite behaviour to party system functioning.