Abstract: Metaphysical libertarianism (hereafter ML) is the doctrine that human beings possess free will, that free will is incompatible with determinism, and that determinism is false. In this paper, I argue that the philosophical viability of political and economic libertarianism (hereafter PEL) depends on the viability of ML. Compatibilism is the doctrine that determinism is compatible with free will, and hence possibly also with PEL. I attempt to undermine this contention by exploring the relationship between compatibilism and prepunishment – i.e., the practice of punishing people before their commission of a crime. I make a claim that considerations of prepunishment, as well as related advance actions, which I collectively call “preactions”, not so much reveal and underscore the radical consequences of compatibilism, but rather, firstly, threaten its collapse into hard determinism, and secondly, cast a shadow of suspicion on determinism itself, thus opening some new, promising avenues for ML, and, by implication, securing the philosophical foundations of PEL.