Why can't we build a 10 meter high concrete wall from the Pacific to the Gulf of Mexico and be done with the problem? The engineering is not that big a deal, and the cost could be pretty reasonable with the proper design.
So why not do it?
Because a simple concrete wall doesn't do the job. The Israelis have the right idea, the right design, and the right implementation.
How many YEARS would such a wall take?
We could even have Mexican illegals build it on the cheap! ROFLMBO!