Sorry for making fun, but it seems to me...
If you make it legal for people to buy and grow marijuana for medicinal, recreational and other productive uses, (ie, paper), they can get it on an open market at a price that won't be near as much. The crime lords won't have a monopoly or anything close to their current profit. They can't whack all the competition. (I suppose they would just suppliment their income another way. Meth, heroin, cocaine, re-sell chinese drywall?)
BTW, Marijuana is so easy to get now, legalizing it would not increase the amount of recreational and self medicating users significantly in the long run.
Who's against legalizing it? Anyone that is at risk to losing money from it.
And the reason I'm on the site today, is I found this little ditty.
Medical marijuana user can have concealed handgun permit, court rules | DailyTidings.com
Medical marijuana user can have concealed handgun permit, court rules
June 16, 2010 The Oregon Court of Appeals ruled against Jackson County Sheriff Mike Winters today in a case in which he denied a concealed handgun permit to a medical marijuana user.
The ruling upholds an earlier decision by Jackson County Circuit Court Judge Mark Schiveley, who ordered Winters to grant renewal of Cynthia Willis' permit in 2008.
In its ruling, the Court of Appeals found that Willis complied with state law in her application, and found no credible legal argument from Winters as to why he denied the permit.
"In sum, we are not persuaded that the Sheriff is being forced to violate — or even potentially violate — any federal law by issuing a concealed handgun license pursuant to Oregon's concealed handgun licensing statutes," the court ruled.
— Damian Mann