I understand that your main issue is border security, but that does not preclude free trade with Mexico, Central and South America.
NAFTA was supposed to help create a thriving Mexican middle class that would then be far less likely to (both legally and illegally) immigrate to the U.S. looking for work. But as you probably know that hasn't happened, and the stampede across the border continues.
In fact, NAFTA put a huge number of Mexican farmers out of business because they could not compete with US agribusiness. .....so they come up here.
The same thing will happen with Central America because of CAFTA.