Becker and Posner prove they're smarter than me on illegal immigration. I do think there needs to be a status of guest worker though additionally. A brief overview of how Mexican immigration came to be the way it is: In the thirties (the Depression), the Border Patrol would shoot to kill illegal immigrants. After WWII, we had a bracero program where farm workers could be registered legally to come here temporarily. That was shut off by the Democrats at the behest of unions. Texas culture being antiunion, we just continued the practice without the documentation; in a related practice see 55 MPH speed limit. Then voila'.