As an activist Cousins had many causes, but much of his work stemmed from his horror at the prospect of nuclear war. He saw disarmament and world government as two means of avoiding that catastrophe. This worldview informed both his writing and his activities, which included founding both the Committee for a Sane Nuclear Policy and the Dartmouth Conference. He also served as president of United World Federalists. Cousins played a small but significant role in making possible the Partial Nuclear Test Ban Treaty by carrying a message from President John F. Kennedy to Soviet leader Nikita Khrushchev in 1963.
After becoming ill in Moscow in 1964, Cousins healed himself with laugh therapy. His experience resulted in his best-selling book Anatomy of an Illness: As Perceived by the Patient and an appointment to the faculty of UCLA's School of Medicine. He continued to write and remained associated with the Dartmouth Conference until his death in Los Angeles on 30 November 1990.
Cousins, Norman. Present Tense: An American Editor's Odyssey. New York: McGraw-Hill, 1967.