This article uses the political philosophy of anarchism to critically interrogate the limits of legal authority, showing that the lawʼs claim to unconditional obedience ultimately is unjustified. Here I turn to Walter Benjamin to unmask the violent foundations of legal authority, and to explore critical and radical responses to this - through Georges Sorelʼs notion of the ʻproletarian general strikeʼ, and through Benjaminʼs related notion of ʻdivine violenceʼ, both of which I interpret in a distinctly anarchist way. However, I argue that this deconstruction of the ontological foundations of the law can be turned back on anarchism itself. Anarchism bases its critique of political and legal authority on a kind of organic substratum, one that is scientifically verifiable and morally legitimate, providing the immanent ground for communal relations beyond the law. As an alternative to this foundationalist approach, I propose what might be called an ontological anarchism, which unsettles all established orders. I develop from this an anarchist or, more precisely, post-anarchist, political and ethical project involving an ongoing contestation of legal authority and the coercive practices of state power.