It is going to take a very long time to stop illegal immigrants from entering America. It would take a nexponential commitment of resources including men, money, construction stuff just to maintain some type of barrier and even then it doesn't guarentee they will stop coming. I just sympathise with people who have to do these types of things for reasons to stay alive or making a better future for their children. The question I put is this, Would we do the same thing if we were in their situation?
Just my two cents