I couldn't agree more, but here's the thing.
Human ingenuity and desperation being what they are, no matter how much we beef up the security on our side of the border, they'll keep trying to find a way in. The Viet Cong and the Gaza Strip Palestinians have developed extensive networks of tunnels to avoid security measures on the land. Cubans and Haitians are using boats.
Think outside the box.
It would be more effective to combine increased border security with diplomatic pressure on the Mexican government (to improve enforcement on their own side of the border). I think a third prong of a completely comprehensive solution -- improving economic conditions south of the border, so the illegals don't even want to leave -- would be prohibitively expensive. But the Mexican political leadership might be convinced to become more helpful.
Another thing to consider is to get rid of our employments regulations.
Over regulated employers have more incentives to hire illegals whom they don’t have to obey laws like minimum wage.
That’s why Amnesty is such a stupid idea. The moment these illegals become legal they are no longer wanted by most of their employers, and a new wave of illegals will come in and take those jobs.