“Nationwide, U.S. law enforcement have arrested over 20 million American citizens for marijuana offenses since 1965, yet today marijuana is more prevalent than ever before, adolescents have easier access to marijuana than ever before, the drug is on average more potent than ever before, and there is more violence associated with the illegal marijuana trade than ever before.

Over 100 million Americans nationally have used marijuana despite prohibition, and one in ten – according to current government survey data – use it regularly. The criminal prohibition of marijuana has not dissuaded anyone from using marijuana or reduced its availability; however, the strict enforcement of this policy has adversely impacted the lives and careers of millions of people who simply elected to use a substance to relax that is objectively safer than alcohol.”

http://norml.org/pdf_files/NORML_Real_World_Ramifications_Legalization.pdf