Abstract
Through the 1920s and 1930s, the Berkeley Police Department, renowned as a centre of scientific training and investigation, developed new programmes of predictive policing targeting 'predelinquent' youth. Led by Chief August Vollmer, schools, charities, social services and families throughout Berkeley were coordinated in the ongoing detection of early signs of developing psychoses and personality disorders believed to lead to future criminality. Implying a malleable trajectory of habit formation which might be perverted or corrected, predelinquency warranted psychiatric surveillance across the community to assist Berkeley's police in identifying, mapping and correcting at-risk children. This paper examines how, through the psychiatric category of predelinquency, law enforcement enrolled the community in networks of pre-emptive surveillance with new responsibilities for reporting and correction. In turn, I examine how predelinquency shifted to accommodate various local priorities and anxieties, whereby predictive policing's conceptions of potential threat or improvability reproduced the boundaries of the normative American community.