A sign calling to ban assault rifles is seen in the crowd during a vigil at the Dr. Phillips Center for the Performing Arts for the victims of a mass shooting at the Pulse nightclub Monday, June 13, 2016, in Orlando, Florida. A gunman killed dozens of people in a massacre at the crowded gay nightclub in Orlando on Sunday, making it the deadliest mass shooting in modern U.S. history. (Alex Menendez via AP)