Here in Canada, we also have serious problems with illegals entering our country but we also have a temporary manpower program that allows entry of non-residents, many from Mexico and other Central American countries, to meet employment needs that can't or aren't met by Canadian citizens. it might be something that would benefit the US in areas where such manpower benefits the communities involved.
That said, I still believe that until such time as economies and development in Central America are improved, people desperate to survive and provide for their families will continue to try to get into America for a better life. Europe suffers the same problems from Africa, as an example. It's human nature.