One solution would be for the Feds to get out of the drug enforcement business and leave it up to the states, like 99% of criminal law and enforcement.
Personally, and in the spirit in which this nation was founded, I'd like to see marijuana totally de-criminalized across the country. That would put the drug cartels out of the marijuana business overnight.
That said, I don't mind keeping the laws on the books that make it a crime to distribute it for sale. I also don't want to see Uncle Sam set up a legal regime for the manufacture and sale of the product for tax purposes, like they did with alcohol.
Let folks grow the stuff for their own consumption and leave 'em be.