It isn't like we can bomb and rebuild Mexico, either...unless that is the way to stop the illegal immigration...carpetbomb the southwest desert and rebuild it?
We simply can't afford to destroy Mexico, nor continue to let in illegals.
What we need to do IMO is instill some urgency in the Mexican government to do something about it--not including tossing their problems to us and expect us to solve it for them.
Personally, I like Michael Savage's idea to the situation--in addition to building the wall, we really ought to demand a free barrel of crude oil from Mexico for every illegal they throw at us.
With oil prices at the current level, I think the Mexican government will be sick of sending free oil northbound and will seek to solve the problem on their end--if only to stop giving away their oil...