Give our border patrol guns with bullets. Sow the ground with thorns and thistles. Eliminate the water drops. Release trained coyotes to patrol the border. Train buzzards to hover over live people.
Play Celine Dion music from kiosks along the border. Mexicans might think they went too far and head back south... Away from Canada.
Celine Dion might cause them to self-destruct early too! ROFLMAO!