A daily war is waged in schools all over the United States over wall space. Adolescents are using school walls to convey messages, create name recognition, slander each other, or for claiming territorial space. On the other side is the school administration, which paints over and erases these unsanctioned claims to space, power and identity, as it regards these expressions as challenging the authority of the school. In this paper, which is based on 18 months of ethnographic fieldwork in an urban school in California, it is argued that both practices constitute technologies to generate and sustain group loyalties and both channel aggression against other groups: taggers in the form of threats to or attacks on other groups, the school through athletic competitions. Tracing the history of school colors and their link to competitive athletics underscores the symbolic link between school and nation. However, while official symbols of school colors represent the legitimate and sanctioned identity of the school that is regarded as instrumental to developing esprit de corps, graffiti and tagging represent the illegitimate and criminal/ized identity of gangs and tagging crews. Examining the ongoing battle over wall space and claims to power/identity between school authority and taggers, it is argued that both constitute technologies of power that, while competing with each other, also mutually reinforce each other's claims to power over allegiances through the very process of contestation.