Would definitely get the cartels out of the mix. Since the U.S. is the world's biggest drug consumer, legalization, and effectively ending the black market for drugs, could have positive effects worldwide.
"...the successful annihilation of organized crime's subculture in America would rock the 'legitimate' world's foundation, which would ultimately force fundamental social changes and redistributions of wealth and power in this country. Meyer Lansky's dream was to bond the two worlds together so that one could not survive without the other." - Dan E. Moldea