Vasili Arkhipov prevented escalation of the cold war by refusing to launch a nuclear torpedo against US forces.

The longstanding international nuclear arms race presents us with the following dilemma. Integrating the advancements of flying saucers into terrestrial technological culture would not lead to peaceful applications, at least initially. Under current world conditions such technology would first be used to devise more hellish ways for us to destroy one another.
This story of how nuclear war almost started during the Cuban Missile Crisis should serve as a stern warning. The willingness of UAP intelligences to interfere with the storage and readiness of nuclear weapons is not a national security threat in my opinion. It is a message to the peace-loving people of our planet that these instruments of genocide should be forever abolished.