After the shootings at Columbine High School, many public schools increased their visible security measures, such as use of security cameras and guards. This study assesses this policy response. Particular attention is given to the fear that prompted changes in school security, the types of visible security measures adopted by schools after Columbine, and the positive and negative consequences of these measures. Synthesizing the relevant literature highlights the lack of evaluative work regarding the effectiveness of school security and how little is known about the impact of security measures on students' civil liberty and privacy interests. Gaining a better understanding of school security can help officials make more informed decisions in response to rare, but highly publicized, violent crimes such as Columbine.