In recent years, as nuclear disarmament worldwide has slowed to a crawl, world powers are engaging in a new kind of arms race: a technological one. Today's nuclear threat is not about who has the most nukes, it's about who has the smartest ones. Arms control expert Kelsey Davenport joins Ian Bremmer on GZERO World to talk about the world's long fascination with these horrible weapons and how close we still remain to all-out nuclear war.