One of the major problems with supply reduction efforts (source control, interdiction, and domestic enforcement) is that, "suppliers simply produce for the market what they would have produced anyway plus enough extra to cover anticipated government seizures."

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, 1994), p. 6.
http://www.rand.org/pubs/mono…