We've already declared their drug cartels an enemy. Have you read about the National Guard troops who were run out of their post on the border this week?
Yes, Joanie has a link to the same story right in this essay. We station our soldiers on the border, tell them that all they're there for is "administrative duties," and then expect them to face armed criminals who wouldn't think twice about offing them. Disgusting doesn't begin to describe this situation.