This is a must read.  Fascinating article comparing and contrasting various narrative frames related to President Truman's use of nuclear weapons against the Japanese at then end of World War II in Hiroshima and Nagasaki.  The traditional narrative is the "Triumphant" narrative that embraces the decision as appropriate and likely to have saved millions of lives both American and Japanese as opposed to the alternative of invading the mainland.  The second is the "Tragic" narrative that criticizes Truman for unleashing such misery since the Japanese were closer to capitulating than is normally described in the history books (especially after the Soviets were gearing up to declare war).  The final, and most interesting, is the "Apocalyptic."  Not only criticizing Truman for inflicting misery on the Japanese, but also essentially for bringing an existential threat to mankind into force.  After the bombings it should have been easy to see that the Soviets would enter an arms race that could lead to the "end of the world."

Of course, with the Cuban Missile Crisis we did nearly see that apocalyptic vision come to fruition.  Also, it is amazing to me that for decades our defense (and the defense of the world) was premised on the concept of "Mutual Assured Destruction" (MAD).  We wouldn't destroy the Soviets because they could destroy us and vice versa.  What a strategic concept.  Stability maintained under a mushroom cloud of extinction.  Only recently have we begun to move beyond that.  However, the threat of MAD while far less than at the heigth of the Cold War, is still existant.  Now we face terrorist nuclear bombings and, though almost unthinkable, both the Russians and us still point missles at each other.  Imagine an accidental launch from either side...

I don't think its Truman's fault.  The weapons were already developed before he bacame President and someone would have embraced them at some point, it could not have been hidden from the prying eyes of other nations looking for an advantage.  That said, he is the person who did the final act of firmly opening Pandora's Box and we all live in that towering shadow.