The United Nations is expected to hold the tenth Nuclear Nonproliferation Treaty (NPT) Review Conference in 2021, following its spring 2020 postponement. In this event, panelists discuss the status of the treaty, which has facilitated nonproliferation cooperation for more than fifty years, including the major accomplishments of its signatories and the challenges they face. The Paul C. Warnke Lecture on International Security was established in 2002 and is endowed by a number of Council members and the family and friends of Paul C. Warnke. The lecture commemorates his legacy of courageous service to the nation and international peace.