Okay, let's think this through carefully: A country, using nuclear weapons, destroys a major American city, taking millions of American lives in the process.

Okay, let's think this through carefully: A country, using nuclear weapons, destroys a major American city, taking millions of American lives in the process. America still has at least ten other major cities spread across several time zones, along with the world's largest economy, which supports the world's most conventionally lethal military, which has over a thousand bases around the world. In spite of the attack, the country - in which three hundred million are still alive and kicking - remains very powerful and very rich. Only now, it's very, very angry. In this scenario, would you consider America to be (a) Unlikely to retaliate (b) Likely to retaliate in some limited way after long, anguished deliberation (c) Likely to retaliate swiftly, but on a strictly limited basis, or (d) Likely to firebomb whoever did it back to the stone age with extreme prejudice and absolutely zero hesitation or regret? Given that the obvious answer is D, how - exactly - is the nuclear weapon used in the attack an "equalizer"? Remember, that term is most commonly used in relation to handguns, which allow a smaller, weaker person to cripple or kill a much larger, stronger assailant. Key factor: cripple or kill, not "diminish only slightly while making volcanically furious." This, by the way, was a point made by Machiavelli. He strongly advised Princes against attacking others unless they planned to do so with such intensity that they could be sure that their opponents (and the sons of their opponents) would NEVER recover. "Nothing is more dangerous" he cautioned "than a lightly wounded enemy." In other words, destroying a city - even a major one - won't do. If you want to attack America and survive, you really do need to take down the entire economy. And it that's your goal, you should skip nuclear engineering altogether and just get a job on Wall Street.