Seven mothers united in grief over losing their children to gun violence or excessive use of force by police will put their message in the spotlight tonight when they deliver a speech at the Democratic National Convention in Philadelphia. The group known as the Mothers of the Movement includes Sybrina Fulton, the mother of Trayvon Martin, who was shot while walking in his neighborhood in 2012, and Lezley McSpadden, the mother of Michael Brown, whose death in Ferguson, Missouri, in 2014 at the hands of a police officer set off nationwide protests. Mothers of Trayvon Martin, Eric Garner Offer Emotional...