“It is a mistake to assume that diplomacy can always settle international disputes if there is "good faith" and "willingness to come to an agreement". For in a revolutionary international order, each power will seem to its opponents to lack precisely these qualities. […] In the absence of an agreement on what constitutes a reasonable demand, diplomatic conferences are occupied with sterile repetitions of basic positions and accusations of bad faith, or allegations of "unreasonableness" and "subversion". They become elaborate stage plays which attempt to attach as yet uncommitted powers to one of the opposing systems.”

The Relation of the State to the Invididual (1890)
Context: What relations should exist between the State and the Individual? The general method of determining these is to apply some theory of ethics involving a basis of moral obligation. In this method the Anarchists have no confidence. The idea of moral obligation, of inherent rights and duties, they totally discard. They look upon all obligations, not as moral, but as social, and even then not really as obligations except as these have been consciously and voluntarily assumed. If a man makes an agreement with men, the latter may combine to hold him to his agreement; but, in the absence of such agreement, no man, so far as the Anarchists are aware, has made any agreement with God or with any other power of any order whatsoever. The Anarchists are not only utilitarians, but egoists in the farthest and fullest sense. So far as inherent right is concerned, might is its only measure.

Address to the United Nations Atomic Energy Commission (14 June 1946)
Context: Peace is never long preserved by weight of metal or by an armament race. Peace can be made tranquil and secure only by understanding and agreement fortified by sanctions. We must embrace international cooperation or international disintegration. Science has taught us how to put the atom to work. But to make it work for good instead of for evil lies in the domain dealing with the principles of human dignity. We are now facing a problem more of ethics than of physics.

Faith Today, January 11, 2006, "Faith and Politics: Party Leaders Respond".
2006

2000s, The Real Abraham Lincoln: A Debate (2002), Q&A

Patheos, A Letter to a Certain Christian http://www.patheos.com/blogs/reasonadvocates/2013/10/12/a-letter-to-a-certain-christian/ (October 12, 2013)

Some Reflections on Peace in Our Time (1950)
Context: In the final analysis, the acid test of a genuine will to peace is the willingness of disputing parties to expose their differences to the peaceful processes of the United Nations and to the bar of international public opinion which the United Nations reflects. It is only in this way that truth, reason, and justice may come to prevail over the shrill and blatant voice of propaganda; that a wholesome international morality can be cultivated.

UN expert urges States to be more transparent on military expenditure
2014

Commentary on the Communist revolution in China.
Years of Crisis (1955)

Now is the Time to Prevent a Third World War (1950)