Trump Called Parkland Deputy A 'Coward.' What Has That Word Historically Meant?

President Trump's reference to the school resource officer who remained outside during the shooting at Marjory Stoneman High School as a "coward" sparked a national conversation about cowardice — what it is, and what it isn't.

Here & Now's Robin Young speaks with Boston University professor Chris Walsh, who wrote the book "Cowardice: A Brief History," and says the word should be used carefully.