When twentieth-century American governments tried to control the mis-behavior and crime of children, they did not assume new state duties. Organized societies had always created systems of rules and punishments. Juvenile justice, therefore, provides an appropriate topic with which to begin analysis of childhood policy. A desire to maintain order linked twentieth-century officials with their predecessors through the millennia. Between 1900 and 2000, in addition, children's bad behavior followed predictable patterns. Male adolescents, proportionally, were greater lawbreakers than any other segment of society, five times more likely than were girls to be arrested. Moreover, young criminals were primarily thieves. In this, they repeated the actions of their fellows in other eras and in other societies, as did the alarmed responses of adults.

That reaction was predictable. With reason, almost all societies have treated young, unmarried males as threats to social stability. They were – and are. However, the ways that American governments responded in the twentieth century to the need to make adolescents obey the rules moved into uncharted territory. The juvenile court was an American creation, which no other country embraced so enthusiastically. And while it was a new bureaucratic manifestation of an old state function, it mirrored larger developments: the rise of social science, the legal profession's unprecedented growth, adult concerns about the threats posed by the very adolescent peer cultures that public policy's separations of children into age-specific categories encouraged, and finally, public reaction to the fact that minorities – who by mid-century had far greater access to guns – committed a disproportionate number of crimes.