Jon B. Wolfsthal is the director of the Nuclear Crisis Group and a senior advisor at Global Zero. He was U.S. President Barack Obama’s special assistant and senior director at the National Security Council for arms control and nonproliferation. He serves on the Science and Security Board of the Bulletin of the Atomic Scientists and helps set the time of the doomsday clock.
SEOUL, SOUTH KOREA - MAY 10: South Korea's new President Moon Jae-In speaks during his presidential inauguration ceremony at National Assembly on May 10, 2017 in Seoul, South Korea. Moon Jae-in of Democratic Party, was elected as the new president of South Korea in the election held on May 9, 2017. (Photo by Chung Sung-Jun/Getty Images)
TOPSHOT - US Vice President Mike Pence (2nd R) visits Observation Post Ouellette with his daughters (L) near the truce village of Panmunjom in the Demilitarized Zone (DMZ) on the border between North and South Korea on April 17, 2017.
Pence arrived at the gateway to the Demilitarised Zone dividing the two Koreas, in a show of US resolve a day after North Korea failed in its attempt to test another missile. / AFP PHOTO / JUNG Yeon-Je (Photo credit should read JUNG YEON-JE/AFP/Getty Images)
A man carries fake nuclear barrels during a demonstration to demand the closure of Fessenheim nuclear power plant on March 12, 2017 in Fessenheim, eastern France.
/ AFP PHOTO / SEBASTIEN BOZON (Photo credit should read SEBASTIEN BOZON/AFP/Getty Images)
MINSK, RUSSIA - MAY 9: In this handout image supplied by Host photo agency / RIA Novosti, S-300 long range surface-to-air missile systems during the celebration of the 70th anniversary of Victory in the 1941-1945 Great Patriotic War in the Hero City of Minsk during the celebration of the 70th anniversary of Victory in the 1941-1945 Great Patriotic War in the Hero City of Minsk, May 9, 2015 in Minsk, Russia. The Victory Day parade commemorates the end of World War II in Europe. (Photo by Host photo agency / RIA Novosti via Getty Images)
