Back in 2001, George W. Bush, a newly elected president from a border state, had immigration on his mind. Within weeks of his inauguration, Bush vowed to extend a hand to Mexico, making an ambitious guest-worker proposal a hallmark of his administration. The president's dream was dashed by 9/11; tightening border controls, not loosening them, became the priority. He must have been serious, though, because just weeks after winning a second term, Bush has embraced the guest-worker proposal anew. Secretary of State Colin Powell and White House counselor Karl Rove have called the initiative a high priority. And Bush pledged...