As far as keeping the borders shut down tight, I don't think anyone out East realizes just how open it is. My sister-in-law and I drove the Anapra road yesterday along the border of Mexico and she marvelled that there was so much undeveloped, raw land. There aren't enough BP agents in the country to keep it patrolled. We have so many illegals coming over that the BP can't come and get them because they are too busy getting others.
The only real solution is to support a true democratic republic in Mexico and hope that they would improve their society and they'd want to stay home.
That was part of my point. We can't stop the flow. Wouldn't it be better to remove the incentive for illegal crossing and try to get the people who will cross anyway onto a citizenship track? At the least, it would kill the coyote business.