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 justi...