This is the broken windows theory. The concept linked disorder in a community (and the growing amount of it) to an increase in criminal activity. As people saw that it was the "norm" to commit crimes, vandalism, and the like, it became more prevalent and more widespread. This tended to lead to aggressive practices on the part of authorities when it came to stopping the crime, including "zero-tolerance" practices that were seen as a possible erosion of civil liberties.