Like the United States, India has an immigration problem. India is a developing country with a booming economy. Its neighbor, Bangladesh, is an impoverished mess with 150 million people crammed onto what is mainly a flood plain about the size of upper New England plus Massachusetts. India surrounds Bangladesh on three sides; on the fourth is the Indian Ocean, which frequently stirs up catastrophic typhoons. India's per-capita income is about $730 a year, not much by American standards but twice that of Bangladesh, where nearly 60 million of its residents earn less than $1 a day. The result was a...