Policing and prisons have been the focus of recent community mobilizations in the US, particularly because of their disproportionate impact on Black communities. Along with the excesses of law enforcement officers, vigilante attacks have brought the fatal costs of Islamophobia, anti-immigrant sentiment, and anti-Black racism to the fore of the American consciousness. As a strategy to combat both carceral violence and socioeconomic inequity, scholars in African American Studies and the social sciences have advocated for multiracial alliances between racialized groups and more privileged communities. What, though, are the limits of multiracial coalition building as a tactic for democratic social change? This dissertation answers these questions through an examination of the locally situated practices of progressive institutions and their relationship to the logics of prison and policing. Using a spatial lens, I argue that the local practice of multiracial coalition politics is shaped by the terrain of anti-Black racism, and that the brunt of its impact is borne by Black girls, women, and queer people. I center my data collection on a public high school focused on social justice in San Francisco. The school, which was itself the product of community organizing efforts, serves contradictory functions as both a strategy for activists struggling against systemic inequities, and a site where those inequities are perpetuated, particularly against young Black people. The patterns of racialized inequity within the school were paralleled in a broader suite of forces constraining Black life in liberal San Francisco through gentrification and criminalization. I conceptualize this dynamic as carceral progressivism, a form of late liberal statecraft in which the gains of redistributive social movements are undercut by their collusion in Black disposability and punishment. The aching persistence of anti-Black practices and logics in progressive institutions allows us to do the analytic work of distinguishing anti-Black racism from white supremacy, as well as the political work of devising a notion of multiracial coalition based on the abolition of the former, rather than the amelioration of the latter.