Nicholas M. Gallagher’s thoughtful essay on immigration raises important questions often overlooked in the current debate. He notes, rightly, that the headlines about Central Americans crossing our southern border should be understood in the context of previous ethnic migrations over the last 150 years. He’s also right in arguing that the distinction between migrants and refugees, a relatively recent concept that has now become rooted in law, isn’t a particularly useful way to distinguish among the various people who wish to come to America.