WASHINGTON, DC – DECEMBER 06: Robert Kagan (R), senior fellow in the Brookings Institution’s Project on International Order and Strategy, testifies before the Senate Armed Services Committee December 6, 2016 in Washington, DC. The committee heard testimony on the topic “Emerging U.S. Defense Challenges and Worldwide Threats.” Also pictured are (L-R) retired Army Gen. John Keane, chairman of the Institute for the Study of War and former vice chief of staff of the Army; and Shawn Brimley, executive vice president and director of studies at the Center for a New American Security. (Photo by Win McNamee/Getty Images)