Nuclear weapons have a shelf life that is surprisingly short for smaller more complicated weapons. Tritium dopants and plutonium cores degrade quickly. The cores can be reprocessed but it is difficult.
Smallpox on the other hand is much more likely to just get your home country nuked into oblivion if they find who deployed it. It's effectiveness as a weapon is going to be limited in first world countries with ring vaccination programs and epidemiologists. On the other hand it would be devastating to the countries that would have a ideological reason to deploy them.
Modern terrorism is a game of chicken. You want to be successful enough to degrade the enemy without triggering a backlash. Smallpox and nuclear weapons are great deterrents, however deploying them would mean the end of the countries and organizations using them.
Dr. Strangelove: "Of course, the whole point of a Doomsday Machine is lost, if you keep it a secret! Why didn't you tell the world, EH?"
Smallpox on the other hand is much more likely to just get your home country nuked into oblivion if they find who deployed it. It's effectiveness as a weapon is going to be limited in first world countries with ring vaccination programs and epidemiologists. On the other hand it would be devastating to the countries that would have a ideological reason to deploy them.
Modern terrorism is a game of chicken. You want to be successful enough to degrade the enemy without triggering a backlash. Smallpox and nuclear weapons are great deterrents, however deploying them would mean the end of the countries and organizations using them.
Dr. Strangelove: "Of course, the whole point of a Doomsday Machine is lost, if you keep it a secret! Why didn't you tell the world, EH?"