The New Inquiry, sociologist Harry Levine explains the terrible mechanics propelling apartheid-style law enforcement in America:
Police arrest mostly young and low-income men for marijuana possession, disproportionately blacks and Latinos. In the last 15 years, police and sheriff ’s departments in every major U.S. city and county have made over 10 million of these possession arrests. Most people arrested were not smoking. They were carrying tiny amounts.
Police make so many because they are relatively safe and easy arrests. All police have arrest quotas and often they can earn overtime pay by making a marijuana arrest toward the end of a shift. The arrests show productivity. Making many low-level arrests of all kinds is very good for training rookie police who gain experience doing many stops and searches of teenagers.
There is also a push nationally, to states, counties, and city police departments, to get as many new people as possible into the criminal databases.