Examines immigration records over the last 100 years, mostly in California, to explain the variation in youth crime rates in different immigrant communities using sociological analysis. Early 20th century crime data on the Chinese, Mexican, and Molokan Russian immigrant populations is compared with late 20th century data on crime rates in the Vietnamese, Laotian, Mexican, and Korean communities to illustrate a connection between youth crime rates and migration. Examination of social relationships, especially how the second generation males relate to community elders, and of the effect of economic hardship reveals the basis for conflict within the immigrant populations. The problem is exacerbated when the law enforcement community becomes involved; the police tend to approach the immigrants with preconceived, stereotypical attitudes about the community, the immigrant elders lose their status and ability to maintain societal control as the police enforce unfamiliar laws, and the youth exploit these tensions by increasing criminal behavior. The result is that immigrant populations with high numbers of young males in the second generation who are more quickly socialized into the new culture than their elders are more likely to see a rise in juvenile crime. Based on this historical analysis, youth crime rates in immigrant populations can be reduced if law enforcement monitors demographic data for new immigrant groups to identify a large group of teenage males. Early mitigation programs, such as organized sports and Scouting, may circumvent problems, as well as training police officers and teachers to quickly identify and redirect problem behavior. (IP)