Abstract In this article, a systematic framework has been developed that identifies the key conceivable formal relationships that form the interface between populism and the constitution. It is concluded that while populist constitutionalism is a dead-end category because populism itself does not respect limitations on power, constitutional populism is possible. The various manifestations of constitutional populism are then broken down according to whether populism is capable of effectively influencing the content of a constitution. In the case of genuinely populist content, the various degrees of this influence are illustrated, all the way up to the almost impossible realization of a populist constitution. After a comparative application of these findings to Hungary and Bolivia and their constitutional reforms, the layers and scales at which populism can affect the state are explained using a three-dimensional representation. The article concludes by cautioning against the risks of the common practice among scholars of adjectivizing the noun ‘constitutionalism’, as in the case of ‘populist constitutionalism’, without defining the point at which the adjective corrupts the noun.