Over the past few months, I’ve noticed a new round of references to the white supremacist “great replacement theory,” so I thought I’d offer a post to explain the dark corners from which this came and the nightmares to which it can lead. At its heart, the “replacement theory” argues that immigration — usually of non-white groups, but some sort of menacing “other” — is a carefully orchestrated conspiracy. Immigration is not, in this paranoid view, the result of individuals and families seeking to better their own lives, but the result of a sinister scheme to ruin