CHATTANOOGA, TN - AUGUST 15:  U.S. Vice President Joe Biden speaks at a memorial service to honor those killed In Chattanooga shooting at University of Tennessee at Chattanooga's McKenzie Arena on August 15, 2015 in Chattanooga, Tennessee.  The military is putting on the ceremony to honor the sailor and four Marines killed and to say thank you to the men and women who helped responded when Mohammad Abdulazeez shot up a military recruitment center and a Navy operations support center before being killed by law enforcement, (Photo by Jason Davis/Getty Images)