The case for building a high-tech fence between the United States and Mexico has just been clinched. The only half-serious argument against building such a fence is that it wouldn't work. Now we know that that argument is just so much hot air. Here is Vicente Fox, president of Mexico on the subject:
Kicking off a four-day, three-state tour, Mexican President Vicente Fox said Tuesday that his nation wants to be part of the solution in the immigration debate, not the problem. "We don't set up walls, and that's not the way you're going to fix this situation," Fox said in Spanish to representatives of groups active in Utah's Mexican community. "It's not with fences that we are going to solve this problem."
It's a reliable rule of thumb that if Fox is saying that something is not a solution to illegal immigration then it is very likely to be exactly that.
See here for a good brief discussion of the issue.