Actually, the 4th Amendment applies to non-citizens on US soil as well. Cut off the illegal immigration problem at the border level itself (we have plenty of unemployed that we could give a satellite phone, food, water, a uniform and viewing equipment) and at the employment level. Not that it’s such a big problem. At least around here, “illegals” work harder than 99% of Americans. The stereotype of the Mexican welfare queen is pretty much hooey.