George Kennan was arguably the greatest U.S. foreign policy analyst of the 20th century. He devised the containment doctrine in relation to the Soviet Union, a middle ground between war and diplomacy. When the U.S. was moving toward invading Iraq, Kennan warned: "War has a momentum of its own, and it carries you away from all thoughtful intentions when you get into it. Today, if we went into Iraq, like the president would like us to do, you know where you begin. You never know where you are going to end" (Foreign Affairs, January/February).