It's a pretty nutty opinion that I have that the borders should be opened. The case to keep immigrants out is grounded in racism, xenophobia, jingoism, irrationality, and inconsistency. It's not so crazy an idea that I have. Many who have a knee-jerk reaction against open borders may not be racists or jingoists, but haven't examined the argument fully, or maybe they just don't understand the reasoning for why open borders are best. For that, Phillipe Legrain is here.