Given that the terrorist assaults of September 11, 2001, were conducted by foreigners on our soil, you might have thought that one of the central measures the U.S. government would have taken would be to tighten up its borders, to establish strict security both at our airports and all along the numerous crossing points into the U.S. from our two contiguous neighbors. Progress was indeed made when it came to detaining, interrogating, and deporting illegal entrants at international airports, but along the U.S. land borders, especially the border with Mexico, the situation has remained one of lightly supervised chaos. Immigration...