The well‐known gap between law on the books and law in action often casts doubt on the significance of changes to law on the books. For example, the rise and fall of penal technologies have long been considered significant indicators of penal change in socio‐historical analyses of punishment. Recent research, however, has challenged the significance of apparently large‐scale penal change of this kind. This article clarifies the significance of penal technologies' rise and fall by offering an alternative account of formal penal change, introducing the analytical concept of “legal templates,” structural models of legal activity (e.g., punishment) available for authorization and replication across multiple jurisdictions. Analyzing punishment's templates explains how new penal technologies can be important harbingers of change, even when they fail to revolutionize penal practice and are not caused by a widespread ideological shift. This article locates the significance of punishment's legal templates in their constitutive power—their ability, over the long term, to shape cognitive‐cultural expectations about what punishment is or should be. This power appears only when the template is widely adopted by a plurality of jurisdictions, thereby becoming institutionalized. Ultimately, these institutionalized templates define the scope of future punishment.