I don't want to defend Obama, and, thankfully, I don't have to; I'm critical of his idiotic non-decision decision.
But, at the outset, I have to say it doesn't change a hell of a lot. On 11 September 2001, a terrorist group supported by the Islamofascist government of Afghanistan attacked United States civilians with what could be deemed a "nuclear-level" attack. I have read analyses that claimed the energy released by the bombing, in the form of collapsing buildings, reached the lower levels of a nuclear attack. Of course, a nuclear attack would have added that energy of falling buildings to its total energy, too; but it terms of death and destruction, certainly the attack was nuclear-like. If four bombs have ever managed to kill 2996 people in one attack, I don't know about it, and certainly this is nearly unprecedented if not completely so.
From what I gather, the Bush Administration put out the word that "all options" were on the table, and there was some leaking that nukes were being considered, but I doubt that was ever very serious. Within weeks we were planning a conventional attack. The reason given for setting the nuclear option aside was that the Taliban had nothing big enough to bomb with nukes, but that turned out to be not quite true: Certainly the forces gathered at Tora Bora could have been killed with a small nuclear attack (and likely bin Ladin as well).
But even in the face of such a horrific attack, a terrorist attack directed mostly at civilians, an attack that seemed to blur the boundaries between a conventional-level and nuclear level attack, we never seemed to seriously consider the nuclear option ourselves, and the only talk about it seemed to be for purposes of diplomacy and internal politics, bluffing our enemies and appeasing the large swaths of the American public that wanted irradiated blood.
Some argue that we needed to "preserve the ambiguity" about the use of nuclear weapons that has been maintained since the start of the Cold War. But that begs the question: Is there any genuine ambiguity about our actual policy? From what I can tell, we have a pure negotiating position, a pure bluff, that says, on paper, maybe we'll use them. Our actual policy is that we won't under virtually any circumstances. For there to be some "ambiguity" here, a number of foreign actors would have to believe the bluff, and I'm not sure any do.
Go read the whole thing.