2013/09/18 Headlines: Obama Urges Congressional Response After Latest Mass Shooting; Aaron Alexis Bought Shotgun Despite Arrests, Mental Issues; U.S. Reviews Security Clearances in Wake of D.C. Shooting; Senate Postpones "Stand Your Ground" Hearing; Study Ties Law to Jump in Justified Homicides; U.S., Russia Differ on U.N. Resolution for Syria; Dozens Killed in Latest Iraq Violence; Egypt Arrests Top Muslim Brotherhood Spokesperson; Brazilian President Cancels U.S. Trip over NSA Spying; NSA Order Shows Lower Threshold for Phone Records, No Challenges from Telecoms; Obama: No Deportation Reprieve for DREAMers' Parents; U.S. Poverty Rate Unchanged at 15%; Federal Judge Overturns NOLA Officer Convictions for Danziger Bridge Killings; U.S. Extends Wage, Overtime Protections to Home Care Workers; D.C. Council Fails to Override Veto of Living Wage Bill; Activists Mark 2nd Anniversary of Occupy Wall Street