What Is the ‘Great Replacement' Theory and How Did It Go Mainstream?

The “great replacement” theory, also known as “white replacement" theory, is the false idea that white Americans are being systematically replaced by nonwhite people for control of the country, and it's existed on the fringes of racist ideology for centuries. In the wake of a deadly Buffalo shooting motivated by white resentment, Dr. Jonathan Metzl explains how it moved into the mainstream.