Aaron David Miller is a vice president and distinguished scholar at the Woodrow Wilson International Center for Scholars and author of "The End of Greatness: Why America Can't Have (and Doesn't Want) Another Great President." Miller was a Middle East negotiator in Democratic and Republican administrations. Follow him @aarondmiller2. The opinions expressed in this commentary are his.
(CNN)Donald Trump departs later this week on a whirlwind trip that will take him to the Middle East and to Europe for meetings with Pope Francis, NATO and the G7.