In recent decades in many countries in the world, the criminal justice system has taken an increasing interest in preventing violence before it occurs. For instance, much of community and problem-oriented policing aims to reduce crime and violence by altering the conditions that foster it – and not to increase the number of arrests. Indeed, some police leaders have gone so far as to say the police should primarily be a crime prevention agency. Juvenile justice systems – an important component of criminal justice systems – are largely based on the belief in rehabilitation and prevention. In the US, the criminal justice system has, for instance, funded school- and community-based initiatives to reduce children's access to guns and teach conflict resolution. Despite this, force is used routinely against juveniles by police. In 1974, the US Department of Justice assumed primary responsibility for delinquency prevention programmes and created the Office of Juvenile Justice and Delinquency Prevention, which has supported the "Blueprints for violence prevention" programme at the University of Colorado Boulder.