The presidential-parliamentary distinction is foundational to comparative politics and at the center of a large theoretical and empirical literature. However, an examination of constitutional texts suggests a fair degree of heterogeneity within these categories with respect to important institutional attributes. These observations indicate that the classic presidential-parliamentary distinction, and the semi-presidential category, may not be systemic. This article investigates whether the defining attributes that separate presidential and parliamentary constitutions predict other attributes that are stereotypically associated with these institutional models. The results suggest the need for considerable skepticism of the ‘systemic’ nature of the classification. Indeed, the results imply that in order to predict the powers of a country's executive and legislature, it is more useful to know where and when the constitution was written than whether the country has a presidential or parliamentary system.