"How many YEARS would such a wall take?"
How many years will pass and there will still be no wall in place if nothing is done?
The good thing about you FROBL members is that you keep making the same lame arguments over and over again - and do nothing except convince the undecided that your position is wrong.
How about taking each and every ILLEGAL captured and make their sentence be building the southern wall? That way they can indeed work....that is why they come right?