Will, as always, another well written, thought provoking article.
Unless I missed it, nowhere do you state whether you think this WILL happen, only that maybe it COULD happen...where DO you stand on the likelihood of this occurring?
Are YOU lying awake nights, hoarding food and water, etc. Or is this some kind of twisted revenge on the DU'ers who blasted you for the Leopold thing?

For your scenario to unfold, numerous events (which you plausibly describe, with well referenced facts) must occur precisely in sequence, without variance. If one of these players refuses to cooperate with your scenario, the whole thing falls apart. Not that there isn't plenty of potential for bloodshed and catastrophe, there is, without a doubt. But your scenario seems to suppose that ALL the players are motivated by fear, rage, and/or religious fanaticism.
In order to get to your version of the Apocalypse, you assume there will be no successful behind-the-scenes diplomacy/threats/bribes to persuade any of the players to act differently.
While many of the ME countries have a tenuous grip on stability already, even the loosest of cannons could be convinced to restrain himself for personal profit or self-preservation...your scenario mentions NONE of those possibilities. (Even Tom Clancy and John Le Carre slip some of these twists into their plot-lines

) Unless the launch keys and codes fall into the hands of Hizbollah or Al-Qaida, I think the chances are that Armageddon will be avoided.
Remember, the biggest dogs in this fight (individual wise) are Cheney and Rumsfield. They appear to be more motivated by power and greed. I'm assuming neither one would wish to be a supreme fascist ruler over the US under the circumstances you describe above, and neither would wish to retire in a post-apocalyptic world such as the one in your story. Remember, Cheney has got all those uncashed Halliburton stock options/share, doesn't he? Fat lot of good they'll do him if all hell breaks loose (not to mention if China calls in it's markers).
Speaking of China, along with Russia, they can bring significant pressure to bear on the various players too. You assume everyone will be reacting to the actions of fanatics and madmen, after the fact, with no preventative measures taken.
My theory? Rove and Cheney will milk this for all its worth to avoid their own "Armageddon" in November, but won't LIHOP to the point you describe in your last paragraph- Karl doesn't want to live in an America where you have to go through a military checkpoint to get to the Krispy Kreme drive thru...
Notice I didn't mention Bush in any of this? After this past week, he has proven himself completely, and utterly irrelevant.
So to sum up, Apocalypse Now? Not this week.
Besides it can't happen yet, I'm going to Maui next week.