Today the Washington Post ran an article on human-engineered viruses (registration might be required). While I certainly wouldn't want to discount the threat posed by bioweapons, it seems the press at least is prone to viewing threats in a overly compartmentalized fashion. To protect ourselves from bioweapons, we need stockpiled antivirals or other biological countermeasures, or laws to restrict the proliferation of the technology.
What seems to be ignored, though possibly not by the policy-makers, is the fact that the best way to protect ourselves against bioweapons is to prevent them from being used. Non-proliferation is definitely part of this, but one that is ultimately futile. The genie, as the cliche goes, is notoriously difficult to put back in the bottle.
We have at our disposal a considerably more effective deterrent. Consider that some country, let's call it Malignia, decides it wants to support a war of terror against the United States. Malignia manages to develop or acquire a biological weapon. If Malignian-sponsored terrorists sneak this weapon into this country and release it, it could spread very quickly causing millions or tens of millions to become severely ill or die. In response, we could launch a nuclear strike against Malignia that would completely obliterate its population.
The ability to pursue a disproportionate response to any potential attack from a terrorist state automatically gives us a strategic advantage, and is the nature of deterrence. It would be foolish to ignore this deterrent capacity in any consideration of how to prevent biological attacks.