This chapter challenges Ginsburg & Huq’s schema of constitutional success as presented in the book, Assessing Constitutional Performance. It argues that the unique constitutional dynamic in the United Kingdom - a co-existence of constitutional success and constitutional crisis - highlights a key variable omitted in their calculations: the effective management of constitutional change, or the balance between stability and flexibility in constitutional arrangements. The British experience suggests a contextualized assessment of that balance is a necessary element for establishing constitutional success from a functional perspective.