On July 5, 1955, ten scientists(11th was added later), including those that worked on the A-Bomd asked a rather rhetorical question, "Shall we put an end to the human race, or shall mankind renounce war?". The Russell-Einstein Manifesto, called for nuclear disarmament, an end to warfare in general and urged world leaders to seek peaceful resolutions to their conflicts.
The document, written by Russell with a big assist from Einstein, insisted the choice was as stark as that and it called for abolishing war, while at the same time acknowledging that this would be almost impossible to achieve. Certainly nothing in subsequent world history diminishes that logic. All of the signatories to the Manifesto were Nobel laureates (or soon would be), including Russell and Einstein, who affixed his name to the document only days before his death on April 18, 1955.
The Manifesto maintained that scientists, especially, had a responsibility to speak out against technological threats, particularly nuclear threats, arguing that they understood the consequences far better than even the most astute layman.
One key line to the Manifesto resonates clearly to this day: "Remember your humanity, and forget the rest."