Player Embed Code: Download Embed Share Mattis Speaks at International Institute for Strategic Studies Shangri-La Dialogue Defense.gov June 2, 2018 | 0:51 SINGAPOREDefense Secretary James N. Mattis discusses U.S. leadership and Indo-Pacific security challenges at the 2018 International Institute for Strategic Studies Shangri-La Dialogue in Singapore, June 2, 2018.