[pjc50]

Most of the illict guns causing Mexico's enourmous murder rate come from America, where they are an uncontrolled substance. Therefore America should ban guns? (/s)

Fundamentally it's America's problem. A Chinese crackdown might impair it a bit, but this approach didn't work for Latin America-supplied drugs, and it didn't work for weed, so why do people expect it to work now?

No, the real solution involves getting to the people at risk and helping them. Which is something so completely out of character for the US political system.