In this case, legalization is causing the problem of the U.S. exporting marijuana to countries where it remains illegal. In violation of international treaties.
Not content to merely export our sex and violence, we've now added marijuana. I'm guessing you support the legalization of all drugs, and look forward to the U.S. having the reputation of supplying heroin to children worldwide.
We're #1! We're #1!
Which came first, prohibition or repeal of prohibition?