Abstract: Chapter 9 of the South African Constitution refers to ‘institutions protecting constitutional democracy’ (IPDs). Contemporary constitution designers have written into new constitutions numerous such institutions, and scholars have begun to identify them as a fourth branch of government alongside the traditional legislative, executive, and judicial branches. This article explores some of the conceptual issues associated with the new fourth branch: what justifies the creation of these IPDs (the short answer: a particular type of conflict of interest); what are their generic characteristics (the short answer: they are reasonably permanent institutions rather than ad hoc or statutory ones, unlike their antecedents); what is their relation to a constitutional court – another twentieth-century innovation; and why should they be understood to be a ‘branch’ of government rather than a congeries of useful innovations (the short answer: like the traditional branches, they perform distinctive function not readily performed by institutions located within those branches)?