The borders can't be sealed against laborers as long as the demand for them exists anymore than the borders could be sealed against alcohol during prohibition or drugs today. At best all you can do is drive the price up.
We are in full agreement on that. And a lot of the illegals achieve that status by coming here legally and overstaying their visas. To solve the illegals problem we need to crack down on employers as well as sealing our borders.
But this article was about our borders, national security and a guest-worker program. My comments were responsive to that topic.