"Domestic enforcement costs 4 times as much as treatment for a given amount of user reduction, 7 times as much for consumption reduction, and 15 times as much for societal cost reduction."

Source

Rydell, C.P. & Everingham, S.S., Controlling Cocaine, Prepared for the Office of National Drug Control Policy and the United States Army (Santa Monica, CA: Drug Policy Research Center, RAND Corporation, 1994), p. xvi.
http://www.rand.org/pubs/mono…