Here's another thought I just had about this. My working hypothesis so far has been that Saddam's operatives have been using a antiobiotic-susceptible strain because he wants to be able to keep agents in the field indefinitely, without risking an accidental death giving away the terror network. I further thought it likely that they would switch to an antibiotic-resistant strain for the real attacks or, if for some reason they only have the susceptible strain, they would just go with that and simply accept that only perhaps the 10% of victims at the front of the Bell curve would actually be killed. On reflection, it seems to me that the use of an antiobiotic-susceptible strain could act as a force multiplier in the case of a massive dispersal. If one of these Middle Eastern gentleman were to tip out a jar of anthrax from the top of the Empire State building, as in the scenario you outlined, you'd basically have a situation where everybody on Manhattan Island--I think that's about four million people--could reasonably expect to die without treatment. In that situation, it seems likely that our health care delivery system would be saturated, especially if other Middle Eastern gentlemen carried out analogous attacks on other metro areas at the same time. In such an eventuality, treatment would probably only make a dent in the overall casualty figure. Moreover, the fact that the treatment option exists but would have to be rationed would probably lead to a social breakdown, which would be the force multiplier effect I mentioned.
If this analysis is correct, Bush may not have any choice but to blink. I do think it might be an idea to declare a national emergency and intern Middle Eastern aliens, but it seems the general feeling is this would be a hate crime, and we should all just sit tight and hope for the best.
Use of a pound of Daschle-grade anthrax as that scenario envisages would totally overwhelm any possible health care system. It doesn't need to be antibiotic-resistant.