The whole thought of building a wall is nuts most of them come here to work and employers hire them. Issue a new social security card to citizens with a hologram and photo or a work card same, thing hologram and photo. You get caught hiring someone without those documents the hiring agency, employer pay a fine and go to jail. In the case of the undocumented worker they go to jail with a fine and pay off the fine by work details or programs. When the fine is payed off they work some more to pay for the bus or air fare home. If that does not work the employer can pay there fine and trip home. Part of the military and police basic training can be done on the boarder to help secure it and if individuals are caught packing drugs across its a death penalty. I think the last estimate I heard for the wall was 29 Billion like most government projects Im sure the cost is underestimated. Throw in the cost for environmental concerns and legal proceeding for confiscation of private and Indian lands, maintenance and manning the wall it just does not add up. Then the reality is people escape from prisons do you really think a wall is going to keep them out? Did the Berlin wall or Great China wall work?? Really a wall?