The COVID-19 pandemic has posed an unprecedented governance challenge, with governments resorting to very different (legal) strategies to respond to the health emergency. A rich literature is already dedicated to measures adopted in individual States. This article adds an original comparative contribution to that literature by exploring the influence of specific constitutional features on the legal response to the pandemic and how, in turn, these responses have the potential to reconfigure the institutional frameworks in place. Our analysis shows that both constitutional contexts and legal traditions significantly matter in pandemic times, in particular when it comes to the rule of law credentials of measures adopted. We focus our study on measures taken during first six months of the pandemic (the “first wave”) in four European jurisdictions with significantly different constitutional settlements; namely France, Germany, Italy, and the United Kingdom. Following a contextual approach, the comparative analysis concentrates on four macro-issues: 1) the legal bases of adopted measures; 2) the horizontal allocation of power; 3) the vertical allocation of power; and 4) the role of the judiciary, especially in terms of fundamental rights protection. Across all four analytical categories, constitutional and institutional factors - such as the respective forms of government, vertical power conflicts, presence of pre-existing emergency schemes or legal doctrines, and the structure of the judicial systems - significantly impacted the (legal) path taken in the four jurisdictions under scrutiny and, importantly, reinforced pre-existing patterns of institutional shifts or social and political tensions. In particular, the role of two institutional features generally overlooked in the literature on the matter emerged: the concrete functioning of the vertical allocation of power and the reciprocal relationships between different jursdictions within judicial systems. By these means, this article aims to broaden and enrich the analytical toolkit of the literature concerning the relationship between states of emergency and specific forms of constitutional government and State.