I am NOT at all worried about the so called dirty bomb scenario, with nuclear material wrapped around a conventional high explosive. The threat there is mostly psychological. Unless you're standing next to or very near the device and then it's the actual explosion. But the true nightmare (and I'm sure everyone will agree) is the detonation of an actual nuclear weapon, maybe a thermonuclear weapon on US soil. I've seen recent reports that suggest that 2005 may be the year for such an event.
Well, ExS, I agree. I'm afraid the psychological damage could be severe as the majority of the sheeple don't have much of a clue. Consequently the potential for temporary economic damage would be high.
Thinking of Iran, North Korea, or even Pakistan...
I quite agree that the 'real nightmare' would be an actual nuclear detonation.
I'm not sure, however, that at 'dirty bomb' can be brushed off so easily. It very much depends on what kind of radioactive material is disbursed and where whether the threat is mostly psychological or quite real.
Leaving a few patches of very valuable real estate in the middle of a few cities uninhabitable for decades (or centuries) could have a devastating economic effect. Even having to spend months decontaminating, say Wall Street, the Port of Los Angeles, the neighborhood around the Chicago Board of Trade, and the Port of Galveston could set off a world economic downturn.