The history of policing and criminalization of young Black and Chicanx Angelinos from 1945 to 1965 reveals a central node in the development of L.A.’s Carceral State. Examining the (neo)colonial archives of L.A. law enforcement, probation, think tanks, and public education system during this period illuminates the buildup and devasting impact of L.A.’s youth criminalization regime by various state and private actors. I show that the genealogy of L.A.’s massive youth criminalization regime starts with both the racialized moral panic against Mexican zoot suiters during WWII and the white backlash to the demographic increase of Black residents the following decade were dual sparks to the tinderbox of racial capitalist urbanism which criminalized, incarcerated, and surveilled young Black and Chicanx Angelinos for the second half of the twentieth century. L.A.’s overlapping spatial histories of Spanish and Anglo settler colonialisms, the afterlives of chattel slavery shaping U.S policing, and Cold War liberalism set the structure for how tens of thousands of young people of color labeled as delinquents would have their lives drastically changed in post-war L.A. As white flight increased and racial segregation depended in South Central and East Los Angeles, youth social clubs in two of the cities most impoverished geographies were relabeled by law enforcement and social service providers alike as bastions of zooters, hardcore delinquents, and gangs. Law Enforcement, criminologist, policy makers, and social reformers shaped L.A.’s carceral state to criminalize Black and Chicanx youth in conflict with the law over three decades. Through new discourse, policy, and transformation of policing towards professionalization, young Black and Chicanx Angelinos who were placed in the crosshairs of the carceral state went from juvenile delinquents in the 1940s to “street terrorists” as codified in the California Penal Code in 1987.Through a critical examination of the shifting grounds of L.A’s carceral state via a focus on Chicanx and Black youth policing, I map out a genealogy of L.A.’s “War on Youth” developed through policy, juvenile police training, youth development programing, incarceration, and crafting of criminalizing discourses. Institutional actors and complimentary social, political, and economic forces constructed a hegemonic carceral order that racialized L.A. youth gangs as especially deviant, menacing, and by the 1980s, as terroristic. This shift in focusing on punishment to address youth gang affiliation forever changed the lives of all young Black and Chicanx Angelinos as the material realities as the neoliberal racial capitalist order deepened in the growing post-war metropolis. In L.A. and California at large, the targeting of Black and Chicanx dovetailed as the “tax revolt” took off after the passage of Proposition 13 in 1978. For example per pupil public education spending plummeted in the 1980s and simultaneously California embarked on the largest prison building project the world had seen by construction twenty-two state prisons from 1980 to 2005. From Delinquents to Street Terrorists is a critical intervention into history of the carceral state, the “School to Prison Pipeline” paradigm, and L.A urban history. A key pillar of the phenomenon of racialized mass incarceration as we see today was in fact sowed by L.A.’s juvenile prison expansion, incarceration, and criminalization regime which targeted Black and Chicanx “gangs,” started some twenty years before the canonical Carceral State building project inaugurated with President Johnson’s Federal Prison.