Abstract
The notion that crime can be prevented through environmental design is a recent and promising idea emerging from the fields of architecture and urban planning. However, despite intriguing correlations between crime rates and features of building design, we understand little about the social processes which induce residents to intervene to stop crimes and disorderly behavior in the spaces around them. This article investigates the conditions under which residents of an American inner-city housing project act and fail to act to defend both architecturally defensible and undefensible spaces. Because of the fragmented social fabric, even architecturally defensible spaces here are undefended.