obama gave weapons to Mexican drug cartels to kill as many people as they wanted. The number murdered so far is over 400 men, woman and 16 school children.
1. Obama didn't give them the guns. His peeps allowed them to be bought illegally then tracked them. It's called undercover work, and it's pretty much the only way to unravel criminal organizations.
2. You cannot simultaneously contend that easy access to guns in USA doesn't cause killings, and at the same time claim that these particular guns caused the murders in Mexico.
Do I think the gunrunning was a bad idea? Yes. But it didn't cause those people to be killed.
Anymore than the gift of a.45 to the idiot in Charleston caused the murder of those people.