The Rev. Al Sharpton challenged the National Rifle Association to defend the gun rights of two black men killed in police encounters last week in Louisiana and Minnesota. The victims - Alton Sterling and Philando Castile, respectively - were carrying guns when they were approached by police officers and shot. Video of the incidents sparked protests around the country last week. "Both of them were killed by police based on 'they had a gun,'" Sharpton said at his weekly rally in Harlem. "Now I missed the NRA coming out and defending the gun rights they legally had. Where is the...