Abstract: The American criminal justice system is a system of pleas. Few who know it well think it is working. And yet, identifying plausible strategies for law reform proves challenging, given the widely held scholarly assumption that plea bargaining operates “beyond the shadow of the law.” That assumption holds true with respect to substantive and constitutional criminal law—the two most studied bodies of law in the criminal justice system—neither of which significantly regulates prosecutorial power. The assumption is misguided, however, insofar as it fails to account for a third body of law—the subconstitutional law of criminal procedure—that regulates and often establishes the very mechanisms by which prosecutorial plea bargaining power is both generated and deployed. These hidden regulatory levers are neither theoretical nor abstract. Rather, they exist in strikingly varied forms across our pluralist criminal justice system. This Article excavates these unexamined legal frameworks, conceptualizes their regulatory potential, highlights their heterogeneity across jurisdictions, and exposes the institutional actors most frequently responsible for their content. In so doing, it opens up not only new scholarly terrain but also new potential pathways to criminal justice reform.