Every so often, when the conversation veers toward the societal costs of illegal immigration, one can almost predict the emergence of a tired refrain, delivered with all the sincerity of a child rehearsing lines for a school play. “Who will pick our crops?” they ask, as though this plaintive wail were some profound economic insight rather than the rhetorical equivalent of a fig leaf hastily employed to cover up moral abdication. It’s a question designed not to spark a discussion on the issue, as you’ll often find they can’t discuss much further than that line. It’s brought up as a...