Smallpox attacks might well kill thousands. However, it is once again a matter of effectiveness. As an tool of terror, perhaps it might suffice to so enrage America that a true American Jihad would begin. However, vaccination distribution is nearly in place already, and rapidly coming on line. In six months, the attack would kill only hundreds, perhaps only dozens.
We have a civilian health system highly capable of resisting biological attack, organic, or deliberate. Ebola and the Hanta are great fear symbols, but not great weapons.
Since the 16th of October, more people have been killed by the direct acts of doctors than the total number of people known to have contracted anthrax. The number of deaths caused by antibiotics is higher than the number of deaths from Anthrax.
Plague, Influenza, and the other recommended weapon bugs all have specific characteristics that make them difficult to spread. The use of suicide squads of willingly infected volunteers is still the most simply implemented. That one leaves a clear trail of dead bodies, going back to the perpetrators. There is little doubt that world opinion would insure the deaths of everyone involved in the attack, however futile it might be in real world terms.
Keep in mind, as well, that eventually, the groups involved in any sustained biological attack will incur friendly fire infections. A sudden outbreak of Smallpox in Iraq, happening right now would not evoke a sudden outpouring of sympathy and support from the west. The world intelligence community will certainly note the sudden implementation of mass vaccination against an otherwise uncommon pathogen of any sort.
It is theoretically possible that a wealthy nation could mount an attack on a poor nation using biological weapons, and have some assurance of gaining a significant victory. But against any wealthy nation, with a reasonably good health infrastructure, this type of attack is only capable of inflicting symbolic damage to a large population.
I believe the anthrax attacks have been perpetrated by some flavor of American Isolationist Hatemongers. These groups are the only ones I can see “benefiting” from the haphazard deaths of people which accomplishes no real change on the world political stage other than to encourage public outrage. That perpetrator group is unlikely to have access to smallpox. The Iraqi government already knows that they would be the prime suspects of any use of smallpox, and they have had recent experience with the likely consequences. It would be unbelievably stupid for them to become willing targets for weapons of mass destruction. (Which is our stated intended response to the use of Biological Weapons by another nation.)
Tris
“For there has never been a protracted war from which a country has benefited.” ~ Sun-tzu ~