Confessions of the Father of the Neutron Bomb, Sam Cohen:

The one idea dearest to Teller’s heart was the H-bomb. He and a couple of his cronies applied themselves to devising various schemes on designing such a weapon. All of them turned out to be impractical and most of them unworkable. Which never slowed him down in the slightest for reasons we’ll never know nor will he...One day, Teller announced he would be giving a colloquium on his work. Since this was a pretty fascinating subject that held the potential for providing a bang a hundred or even a thousand times bigger than the A-bomb, he spoke to a pretty full house, that included me.

...The briefing was over, there were lots of questions that Teller handled with aplomb, knowing far more about the subject than most in the audience. Finally there came a question that had nothing to do with whether or not his [h-]bomb was feasible. Instead, it was whether it would destroy the world by causing uncontrollable thermonuclear reactions in the earth’s atmosphere that would cause it to burn up, plus you and me and everyone else. Teller was on his game, as he always was, and replied that he had estimated this terrible possibility and we were quite safe — by about a factor of ten. Now there aren’t too many people who rest comfortably with assurances that mankind’s fate, let alone their own, is on the safe side by a factor of ten, although there are millions of smokers, including myself, drug addicts, sex addicts, who take much greater chances than that with their lives, and they know it. Except that they know it won’t happen to them, which is why many soldiers, at least as stupid as they’re brave, get Congressional Medals of Honor.

Naturally, the next question was: “How accurate is the nuclear data you used in your calculation?” As only Edward Teller is capable of doing, he replied, with a smirk-smile going from ear to ear: “Well, it’s possible that the data might be off by a factor of ten.” Which way, he didn’t profess to know, but I suspect that much of the audience didn’t sleep too well that night. (If you’re beginning to worry that you might not be sleeping too well from now on, I have to tell you that as it turned out, after careful nuclear measurements and detailed calculations were made, we were safe by far more than a factor of ten. It simply couldn’t happen.)

Cohen then goes on to discuss in the next section how egregiously biased & unrealistic was the study RAND performed for the Air Force in order to justify the military utility of h-bombs and hence their development. After mentioning that the nuclear stockpile now reflects Oppenheimer's strategy of smaller warheads, he concludes:

There’s a profound lesson to be learned about the great H-bomb debate; that it was a farce. I’m sure (or am I?) that many scholars now understand how farcical it was, but you’d never know it from their writings. However, whether generals, admirals, congressmen, and Presidents have grasped this, I wonder. In fact, I don’t wonder too much, for as I observe the passing scene with arguments on the Stealth bomber, the MX missile, and all that nuclear business that is supposed to mean so much for our survival, I don’t think they’ve learned a thing. They still carry on in the same way, fighting over expensive nuclear weapon systems they don’t understand, to be used in a war we don’t know how to fight.