A dangerous nuclear moment

In 1963, President John F. Kennedy kicked off a decades-long effort to reduce the risk of nuclear war, when he signed the Limited Test Ban Treaty. Subsequent presidents forged new agreements, but now that global order to safeguard and reduce nuclear arms is deteriorating. This month the last bilateral nuclear treaty between Russia and the United States expired. Meanwhile, President Trump is pushing the international order to a breaking point, and European leaders are speculating about a new path forward for their collective nuclear defense. NPR’s Mary Louise Kelly talks with Christine Wormuth, former Secretary of the Army and now President and C.E.O. of The Nuclear Threat Initiative, about the possibility of a new nuclear arms race.