When central authority fails in socially crucial tasks, mutual aid, solidarity, and grassroots organization frequently arise as people take up slack on the basis of informal networks and civil society organizations. We can learn something important about the possibility of horizontal organization by studying such experiments. In this paper we focus on the rationality, care, and effectiveness of grassroots measures to respond to the pandemic and show how they illustrate core elements of anarchist thought. We do not argue for the (...) correctness of any version of anarchist politics, nor claim that the bulk of this grassroots work was done with anarchist ideas explicitly in mind. Nonetheless, the current pandemic, like many social crises before it, serves as a sort experiment in political implementation. -/- Two things have been striking in the US response to the COVID-19 pandemic: the chaos, incompetence, irrationality, and often cruel misguidedness of the centralized government response; and the rationality, care, and effectiveness of grassroots measures in many parts of the country. In this paper we focus on the latter—especially the case of Washington, DC—to illustrate core features of anarchist politics. We do not argue for the correctness of any version of anarchist politics here, but merely illustrate guiding ideas that have been a part of anarchist theory and practice for well over a century. We also do not claim that the bulk of this grassroots work was done with anarchist ideas in mind, or explicitly out of a commitment to anarchist politics. Some was, and some arises out of related ideological commitments, but most simply functions out of no more than a desire to support one another. -/- The current pandemic, like many social crises before it, rather than providing a stand-alone argument or functioning as an implementation of any political theory, serves as a sort of laboratory experiment. When central authority fails in socially crucial tasks, mutual aid, solidarity, and grassroots organization frequently arise as people take up slack on the basis of informal networks and civil society organizations. We can learn something important about the possibility of horizontal organization by studying such experiments, including how it arises through spontaneous action. If political thought is best illustrated through its implementation in practice, the functioning of grassroots individuals and organizations in a time of crisis is one way to understand the political mechanisms core to anarchist thought. (shrink)