How did Pope John XXIII view peaceful coexistence during the Cold War?

During the Cold War, St. John XXIII viewed peaceful coexistence between the West and the communist East as not only desirable but a necessity for the survival of humankind.1

He articulated this perspective in his major encyclical, Pacem in terris ("Peace on Earth"), which addressed all of humanity and set forth requirements for world peace in human terms. By distinguishing between the philosophy of Marxism and the actual governments it produced, he sought to move beyond the militant, polarized policies of his predecessor, effectively diluting the religious energy that had been poured into the conflict.123

His commitment to peace was also demonstrated through practical diplomacy. During the 1962 Cuban missile crisis, he publicly urged both the United States and the Soviet Union to exercise restraint, earning the appreciation of both John F. Kennedy and Nikita Khrushchev.1