What explains constitutional reform, or, in the case of the postwar Netherlands, the absence of reform? In this chapter, this question serves as the starting point for a reassessment of the boundaries between historical and legal scholarship. For historians, law typically only features as the outcome of a political process. Yet, what if archival sources clearly suggest that legal frameworks, as systems of norms and practices, significantly shape that political process, for example, when varying understandings of “the constitution” enable particular paths for constitutional reform while constraining others? This chapter suggests an improved integration of legal beliefs, practices, attitudes, and norms in political history by borrowing the concept of “tradition” from legal scholarship. Demonstrating how the concept can be employed in explaining Dutch constitutional reform, it contributes to an interdisciplinary conversation that could benefit both law and political history.