How the murders of two Black sons ignited social justice movements

Charles M. Blow is a columnist for The New York Times, and author of "The Devil You Know: A Black Power Manifesto" (HarperCollins).

It was the killing of Emmett Till that Rosa Parks said she was thinking about when she refused to give up her seat on that bus. It was the killing of Trayvon Martin that set off waves of protests that grew for a decade, and culminated in the massive, global "Summer of Protest" after the murder of George Floyd.