http://www.heritage.org/Research/UrbanIssues/bg1834.cfm
Backgrounder #1834
Stephen Johnson and David B. Muhlhausen, Ph.D.
"Youth gangs are nothing new. They appeared in New York City and Philadelphia at the end of the American Revolution. Their numbers and violence correspond to peak levels of immigration and population shifts that occurred in the early 1800s, 1920s, 1960s, and late 1990s. Entrenched in American culture, gangs are romanticized in movies while rap artists copy their dress and jargon. However, because of their growing membership and globalization, gangs have become a public security threat that must be addressed."
