Epidemics have functioned as “forks in the road” of European History, prompting leaps forward in the status quo and power relations. In the language of social scientists, epidemics have worked as “critical junctures”, representing a moment of change in the path-dependent evolution of political systems and institutions, and disrupting social, political, and economic relations. COVID-19 can be portrayed as a crisis of modernity itself in the sense that modernity was built on freedom of movement, the essential condition of liberal markets economics. This contribution analyses the legal reaction to the pandemic from a constitutional state of emergency perspective. Taking the Portuguese situation as a case study it considers constitutional safeguards on the state of emergency and whether this is preferable to the use of ordinary legislation in managing a pandemic crisis.