Above all, I regret that scientific experiments—some of them mine—should have produced such a terrible weapon as the hydrogen bomb. Regret, with all my soul, but not guilt.

I happened to read recently a remark by American nuclear physicist W. Davidson, who noted that the explosion of one hydrogen bomb releases a greater amount of energy than the explosions set off by all countries in all wars known in the entire history of mankind. And he, apparently, is right.
[The quoted physicist was, in fact, William Davidon, Argonne National Laboratory.]

The fact that no limits exist to the destructiveness of this weapon [the 'Super', i.e. the hydrogen bomb] makes its very existence and the knowledge of its construction a danger to humanity as a whole. It is necessarily an evil thing considered in any light. For these reasons, we believe it important for the President of the United States to tell the American public and the world what we think is wrong on fundamental ethical principles to initiate the development of such a weapon.