If for no other reason I would say legalize it just to put the drug lords out of business. Legalize it and tax it! The price would go down due to competition and not having a risk of going o jail for growing it, additionally the tax on the crap could be high enough that prices just level out to about what they are now and we end up with a nice new stream of revenue without the price climbing to where there would be much of black market for the product. With this done the drug cartels shrink and weaken making them easier to defeat as law enforcement would be able to use more resources for eradicating our country of the more harmful drugs such as crack, meth, opiates, etc.