1. Thread about immigration, inspired by Bernie Sanders' latest bout of nativism and by what @skinnylatte keeps getting in her mentions.
The starting point is that immigration in the US and Canada is fairly high-skill these days (e.g. post-2000 immigrants have higher education levels than natives), and that it especially lands at the highest- rather than lowest-end places - the most elite universities, the richest cities, the highest-paying tech firms.