SEALING THE BORDER HAS BEEN PROVEN IMPOSSIBLE
We tried to seal 66 miles of the border in 1994 in “Operation Gate Keeper” designed by the military. It incorporated double and triple fences (some concrete and steel), guard towers, flood lights infrared cameras, ground sensors, patrol roads, horse patrols, ATV patrols, 16 helicopters, fixed wing aircraft, unmanned aerial vehicles, trucks, and a ratio of 32 guards per mile.
If it was successful the plan was to extend it from San Diego to El Paso. It wasn’t successful at all. See Inspector General’s Report: "experienced agents were estimating it was only 5-10 percent effective"
About two hundred thousand are caught each year trying to cross, and another estimated 30 to 40 thousand make it across undetected. They dig under, climb over and break through the fences.
That’s an average of 454 to 606 per mile per year. Extrapolated just to the 2000 mile Mexican border that would be about 1.2 million border jumpers per year. And we would still have the ones who enter from Canada or by air and water or legally on temporary visas and don’t return.