They're being murdered because of our own un-pragramatic religious and ideological interpretation of the 2nd Amendment. I agree with the right to bear arms, but there should a limit. A hand-gun with a limited magazine seems reasonable, an assault rifle with armor piercing bullets and an extended magazine doesn't.

In 2005 when the assualt weapons ban was lifted the cartels were able to get their hands on a cheaper and better source of weapons. The balance of power shifted more to the cartels as they were able to get better weapons. We should be helping Mexico because the cartels are beginning to look like an insurgency.

Edit: If you're downvoting me can you at least try to explain why it's not our fault that our weapons sold in the US are being used to murder civilians and contribute to a narco-state? Felipe Calderon even said this as recently as yesterday on Bloomberg.