I agree about going after the businesses that employ illegals, but I think the wall would absolutely act as a deterrent for illegals, drug smugglers, etc.
At what cost would a wall deter illegals? How much of an effect will it have versus the cost? That's why i don't think its an overstatement to say the wall is a stupid idea. Hell, listening to all the slams on Canada and its socialism would make me want to go there if i was an illegal. Is there a illegal immigration problem there?
Cracking down on employers far more than we are doing now is the answer. Also making it federally illegal for states to allow illegals to have driver's licenses, register cars, get government aid, etc. will go a long way.
It seems, the people/companies financially support both republican and democratic representatives do not want that. They will however, settle for allowing them in to get votes, or to keep them out to get government money to spend billions on a wall, that isn't the answer to the problem.