In 2014, protesters ringed the White House, chanting, "How many black kids will you kill? Michael Brown, Emmett Till!" Why did demonstrators invoke the name of a black boy murdered six decades before? In 1955, white men in the Mississippi Delta lynched a fourteen-year-old from Chicago named Emmett Till. His murder was part of a wave of white terrorism in the wake of the 1954 Supreme Court decision that declared public school segregation unconstitutional....