In 1968 Harvard University political scientist James Q. Wilson published his classic study of two kinds of police departments. The West Coast model was the "professional" department run along centralized, bureaucratic lines, with officers who were recruited on the basis of achievement and had few ethnic ties to the neighborhoods they patrolled. The East Coast "fraternal" police department, on the other hand, was "ethnically particular" and informally organized. Recruits were less educated, hired through ethnic connections and often assigned to the same areas where they were reared.
Fraternal officers, Wilson said, were more likely "to urge restrictive and punitive rather than therapeutic measures" in dealing with criminals, more prone to corruption and police brutality, and more reliant on the discretion -- and prejudices -- of individual officers. Wilson did not specify which cities best represented each paradigm. But Elijah Anderson, a sociologist at the University of Pennsylvania, put it bluntly: "The ideal typical fraternal department is clearly Philadelphia."
A little background in why “East Coast” progressives emphasize criminal justice reform 
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