Player Embed Code: <iframe width='500' height='300' scrolling='no' frameborder='0' style='border: none; overflow: hidden; width: 500px; height: 300px;' allowtransparency='true' src='https://www.dvidshub.net/video/embed/646264'></iframe> Download Embed Share Defense Leaders Speak at 'Transformers: Defense' Summit Defense.gov Dec. 6, 2018 | 01:34:28 Defense Department leaders speak at the Washington Post's "Transformers: Defense" summit in Washington, Dec. 6, 2018. Marine Corps Gen. Joe Dunford, chairman of the Joint Chiefs of Staff, discusses some of the ways that the Pentagon is modernizing America's armed forces, and Steven H. Walker, director of the Defense Advanced Research Projects Agency, describes ways that the United States and other nations are using next-generation technology in warfighting and military strategy.