SURGE to Stop the Illegal Alien Mob! MAGA! WINNING!
Supplement the troops on the ground with the presence of AC-130 gunships, A-10 Warthogs, and frequent low-level passes with assault helicopters. That should provide plenty of shock and awe up close and ugly for even the most intrepid of adventurous souls that approach the international boundary with malice aforethought.
As a famous lib once said, stroke of the pen, law of the land. Karma.