Covid-19 has exposed major weaknesses in the United States’ federalist system of public health governance, which divides powers among the federal, state, and local governments. SARS-CoV-2 is exactly the type of infectious disease for which federal public health powers and emergencies were conceived: it is highly transmissible, crosses borders efficiently, and threatens our national infrastructure and economy. Its prevalence varies around the country, with states such as Washington, California, and New York hit particularly hard, but cases are mounting nationwide with appalling velocity. Strong, decisive national action is therefore imperative.