"Some 750 agents swept northward...
By the end of July, over 50,000 aliens were caught...
Another 488,000, fearing arrest, had fled the country...
By September, 80,000 had been taken into custody in Texas, and an estimated 500,000 to 700,000 illegals had left..."
If the bracero program (in effect since 1942) resulted in "an estimated 500,000 to 700,000 illegals" who were only driven out by REAL enforcement, I see it as prove that ENFORCEMENT reduces illegals & Guest Workers Programs don't.
Whatever works and if that's a fence then the Government better get on it and start building.