[VeritatisSplendor]

It doesn't have to be in a backpack. It could be as large as a washing machine and be transported in any old ship into New York harbor. Smuggling it into an interior city would be somewhat more difficult.

[ProudFossil]

I would like to suggest a different danger. Instead of having to smuggle large, heavy, clunky devices around, what of the possibility of a quart of Anthrax being placed in a water system, or smallpox germs being dumped into an air conditioning system, or any of a thousand biological and chemical compounds which would act just as quickly and much more deadly. How would you feel if you did not know if the water coming from your kitchen faucet was poison or if that cool (or heated at this time of year) air blowing over your desk was going to drop you in your tracks? The dangers in this war are much, much more insidious than bombs or suicide missions.

[AppyPappy]

That's what people don't realize. You can put a warhead in a Ryder truck and do the same thing. Only they leak after a while. My understanding is they are easy to find with detectors.