Nuke Terrorist Attacks News Today

Some mail delivery is being canceled, streets closed. a lot of security as the world leaders gather in washington, shannon. >> shannon: i feel a lot of mass transit happening this weekend. forget driving or parking. >> you got it. >> shannon: tensions between iran and the west can no doubt be a subject at the summit. joining us, sam youngman and jonathan wiseman. thank you both for coming in today. >> thank you. >> sam, what do you think is the top issue for most of the countries gathered here t...