The mass shooting in Buffalo has placed a spotlight on the racist conspiracy theory embraced by the suspect. Prior to the attack, the suspect allegedly wrote a 180-page manifesto making reference to the "Great Replacement", even using the same language as other convicted mass shooters. Molly Jong-Fast, contributing writer at The Atlantic and author of the Wait, What? newsletter, explains the conspiracy theory, why it's so dangerous, and what can be done to stop it from spreading even further.