While it is true that nuclear development could make some nations "nervous," Bush is not just doing this on a whim. These nuclear bunker buster weapons (which will be smaller tactical nukes, not nearly as powerful as the ones dropped on Hiroshima) are being designed specifically to take out underground chemical weapons plants.

While we do have conventional bombs that can burrow into bunkers, the expolsion they cause would only serve to spread all of the deadly chemicals high into the atmosphere, because the heat they produce is not high enough to destroy these biological weapons. Only a nuclear weapon would produce enough heat to vaporize any harmful material. The question is which is better: the development of these burrowing nukes or risking a deadly outbreak of some horrible virus, i.e. anthrax.