I wouldn't say solutions are unimaginable. For anthrax, an effective and reasonably safe vaccine could well be enough. Speaking of the anthrax vaccine, haven't the Russians offered to sell or give theirs to us? Why haven't we taken them up on the offer -- is there some reason to think their vaccine is ineffective or excessively prone to side-effects?
I don't know about a vaccine for anthrax, anyway it couldn't be given to 300 million of us before 2002.
The next and major anthrax attacks could already be in the mail, or could go down the subway tracks tomorrow.
As far as keeping 100 kilos of antrax spores out of the USA, how successful are we with cocaine interdiction?