Would there be a drug trade if not for the demand from the USA?
What is your point? Exactly how would you shut off demand? If we did a better job of interdicting drug smuggling, the price of drugs would go up making them less affordable. We can address our domestic demand problem thru education and law enforcement, but we cannot allow our sovereignty to be violated by allowing drugs or any other banned commodity for that matter to enter this country illegally. Do we have national borders or not?