Clear an area on the U.S. side. This will go from the border to about 200 yards north.
First, install a razor-wire fence approx. 15 feet high (right on the edge of the border - the whole border).
Next, (going north) allow 20 yards from the first razor-wire fence and install a second one - of the same proportions.
Next, (still going north) allow a distance of 150 yards from the 2nd razor-wire fence, and lay down a shit-load of land mines.
After the land mine zone, install a 3rd razor-wire fence.
After the 3rd razor wire fence, go further north 10 more yards and install a 20 foot high concrete wall with guard towers. The guard towers will be put in place every 200 yards for the length (east/west) of the border. Each guard tower will be armed with snipers.
Some may try to get to the US this way, but once the bodycount steadily rises with no new illegals coming through the US/Mexico border, folks might start to get the message that they are not wanted here.
Motherfucking problem solved.
Hot Forum Topics
