Collective forms of participation in criminal justice from members of marginalized groups—for example, when people gather together to engage in participatory defense, organized copwatching, community bail funds, or prison labor strikes—have a profound effect on everyday criminal justice. In this Essay I argue that these bottom-up forms of participation are not only powerful and important, but also crucial for democratic criminal justice. Collective mechanisms of resistance and contestation build agency, remedy power imbalances, bring aggregate structural harms into view, and shift deeply entrenched legal and constitutional meanings. Many of these forms of contestation display a faith in local democracy as a tool of responsive criminal justice, while simultaneously maintaining a healthy skepticism of the law and existing legal institutions that maintain the status quo. These forms of resistance and contestation are not antagonistic, but agonistic; not revolutionary, but devolutionary. Without facilitating critical resistance from below, well-meaning criminal justice reforms are in danger of reproducing the anti-democratic pathologies that plague our existing system. Indeed, it is from the voices of those who have been most harmed by the punitive nature of our criminal justice system that we can hear the most profound reimaginings of how the system might be truly responsive to local demands for justice and equality. This Essay concludes by sketching out the dual roles of the state in a criminal justice system that values contestation: to facilitate methods of participation that originate with and are led by non-elite actors from marginalized populations; and to create criminal justice institutions that transfer agency and control to people ordinarily left out of criminal justice decisionmaking.