Defense Secretary Jim Mattis, center left, greets South Korean National Security Advisor Kim Kwan-ji during a visit to Seoul, South Korea, Feb. 2, 2017. DoD photo by Army Sgt. Amber I. Smith - Defense Secretary Jim Mattis, center left, greets South Korean National Security Advisor Kim Kwan-ji during a visit to Seoul, South Korea, Feb. 2, 2017. DoD photo by Army Sgt. Amber I. Smith