I don't mind "NINE BILLION DOLLARS", especially if it would cost more to round 'em up, deport, and completely seal the border. Unfortunately, lesser events have indeed caused recessions, but just because no one knows the total costs and benefits, I will not claim you are "totally ignorant of the facts" - now, do you want a calm, rational debate, or not?
The cost estimates for an Israel-style wall or Duncan Hunter's double fence at 15' is less than $3 Billion to build from the Gulf of Mexico to the Pacific Ocean.
Building that barrier then frees up border patrol personnel to concentrate on interior enforcement. That means no new net cost for an activity that up until a year ago wasn't happening. Did you know that until last year, ICE only had one agent assigned to the duty of rounding up illegals in North Carolina? And before you go telling me that NC isn't a border state...they have one of the higher concentrations of illegal aliens in the country after the four border states and Illinois.
The illegal alien is a problem of enormous proportions, whether you want to admit it or not. Accepting it as a fait accompli at this point is weak-willed and ill-advised...it's just plain wrong.