When entering into these talks, U.S. diplomats should first refer to the greatest thinkers in the U.S. international relations tradition, Hans Morgenthau and Reinhold Niebuhr. Morgenthau states that a fundamental duty of statesmen is to cultivate the mental ability to place themselves in the shoes of their adversaries. This does not necessarily mean agreeing with them. What it does lead to is an understanding of what your opponents see as the vital interests of their countries, and what they see as secondary interests, on which they will be prepared to compromise.