NPR's Ayesha Rascoe talks to Heidi Beirich, co-founder of the Global Project Against Hate and Extremism about the prevalence of racism in modern political discourse.

In a rare move, the White House took down a racist post last week from one of President Trump's social media accounts. But extremism researchers say it fits a pattern of mainstreaming extremist ideas.

Being an aide to Rev. Martin Luther King Jr., as well as one of his companions in Memphis, Tenn., on April 4, 1968—the day the leader of the civil-rights movement was shot and killed—conferred a ...